REPORT Fish of Walnut Lake...... 25 OF THE Condition of fish...... 25 STATE BOARD OF GEOLOGICAL SURVEY Species, relative numbers and economic importance OF MICHIGAN of the fish...... 25 FOR THE YEAR 1907 Methods of fishing...... 26 Annotated list of fish in Walnut Lake...... 26 ALFRED C. LANE The Flora, by C. A. Davis...... 36 STATE GEOLOGIST Relations of plants to animals ...... 36 OCTOBER, 1908 Requirements of plants ...... 36 BY AUTHORITY Adaptation of plants ...... 36

LANSING, MICHIGAN Law governing plant distribution...... 37 WYNKOOP HALLENBECK CRAWFORD CO., STATE PRINTERS Types of water plants and their associations...... 37 1908 Factors controlling plant distribution in a given lake ....37 A BIOLOGICAL SURVEY OF The lake a desert ...... 37 Walnut Lake, Michigan. Reasons for zonal arrangement of plants ...... 37 Invariable order of the zones...... 37 BY Limits of the different zones ...... 37 THOMAS L. HANKINSON. Zones above the water level ...... 38 WITH CHAPTERS ON THE PHYSIOGRAPHY, GEOLOGY Ideal classification of the plant zones of the region AND FLORA OF THE REGION BY CHARLES A. DAVIS; AND about Walnut Lake ...... 38 A PAPER ON THE AQUATIC INSECTS OF THE LAKE BY JAMES G. NEEDHAM. Reasons for variation from the ideal arrangement...... 38 The plant zones of a lake affected by the soils of the A REPORT OF THE BIOLOGICAL SURVEY OF THE STATE OF MICHIGAN, bottom ...... 38 PUBLISHED BY THE STATE BOARD OF GEOLOGICAL Application of principles to the flora of Walnut Lake ....38 SURVEY AS A PART OF THE REPORT FOR 1907. Relations of soils to zonal distribution...... 39 Marl ...... 39 Contents Stony or gravelly soils ...... 39 Black mud or impure peat ...... 39 Letter of transmittal...... 2 Effects of aquatic and marsh plant associations on Introduction...... 3 their habitat...... 39 The plant zones represented in the lake...... 40 Acknowledgments ...... 4 The sedge zone ...... 40 Equipment and methods of work...... 4 The bulrush zone ...... 41 Nomenclature and measurements ...... 5 The pond-weed zone ...... 41 Physiography and Geology, by C. A. Davis...... 5 The water-lily zone ...... 42 Location and description of Walnut Lake ...... 5 Water crowfoot ...... 42 The bed rock...... 6 Other zones...... 42 Glacial Geology of the region ...... 6 Flora of the highlands...... 43 Post-glacial history of the region ...... 8 List of plants collected at Walnut Lake...... 43 Marl...... 9 The Fauna of Walnut Lake...... 45 Peat ...... 9 Human agencies...... 9 Summary and conclusions ...... 49 Soils of the drainage basin of Walnut Lake ...... 10 Appendix I. Description of apparatus and methods Physiographic features of the lake shores ...... 10 of recording observations...... 50 Field stations...... 11 Collecting apparatus...... 50 Barren shoal type...... 11 Equipment for making observations...... 52 Bulrush-covered shoal type...... 16 Equipment for making records...... 52 Swamp loosestrife-fringed type...... 17 Appendix II. Data on stomach contents of fish taken Marsh bay type...... 18 in Walnut Lake...... 53 Bulrush shoal type...... 20 Swampy shore type...... 21 Deep water type...... 22

Annual Report for 1907 / Walnut Lake – Page 1 of 66 Appendix III. Notes on the aquatic insects of Walnut Lake with especial reference to a few species of considerable importance as fish food, by James G. LETTER OF TRANSMITTAL. Needham...... 56 OFFICE OF THE STATE GEOLOGIST, LANSING, MICHIGAN. Figures To the Honorable, the Board of Geological Survey of the State of Michigan. Figure 18. Diagram showing results of gas analyses ...... 24 Hon. Fred M. Warner, President. Figure 19. Chironomus albistria Walker. m, The Hon. D. M. Ferry, Jr. epipharyngeal comb of the larva; n, the labial border; both x 55...... 58 Hon. L. L. Wright, Secretary. Figure 20. Unknown Chironomus larvæ from stomach of Gentlemen:—I have the honor to transmit herewith, whitefish; p, epipharyngeal comb, x 310; q, labial border, received from Chief Field Naturalist, A. G. Ruthven, for x 55...... 59 publication as a part of the Annual Report for 1907, a report on the results of a biological survey of Walnut Figure 21. Semi-diagrammatic figure of the buccal apparatus of the larva of Chironomus viridicollis V. d. W., viewed Lake, Michigan, by Thomas L. Hankinson and from below, the mandibles, x, and maxillæ, y, spread out associates. This report is a contribution from the laterally, and the top of the mouth moved a little anteriorly Biological Survey of the State of Michigan, which the so as to show all of the epipharyngeal armature (based on Legislature authorized you to supervise and execute by drawings by Mr. H. R. Stewart). The line i i represents the Act No. 250 of the session of 1905. It consists of a labral margin of the mouth; the parts above it are on the report on the fauna (particularly the fish) of Walnut Lake, front of the head, outside the mouth; the parts below it are and contains much of a practical nature on the economic in the roof of the mouth. The ill defined fringe of fine relations, habits and distribution of the several species, bristles along this margin has sometimes been designated special attention being given to the occurrence of the as the anterior comb. f, the pedunculate palps (only their peduncles are shown in Miall and Hammond's The white fish in this lake. Harlequin Fly Fig 16), g, frontal sensory hairs; h, h, labral This report was undertaken very largely at the or external rakers; i, i, lateral papillæ; k, epipharyngeal (or suggestion of Captain Clark of Northville, with the hopes posterior) comb; I, I, epipharyngeal or internal rakers; m, of obtaining a practical result in connection with the pure m, lateral arms; n, n, anterior cross bar ;1 o, o, U-bar; p, maxillary palpus; q, lacinia of the maxilla; r, scientific treatment. We hoped to find out why white-fish hypopharynx?; z, the labial border, heavily chitinized (in flourished in this lake, what it was in the surroundings situ, the mandibles swing obliquely downward against this that made them thrive, so that we might know where border)...... 59 whitefish might be successfully planted and raised. Figure 22. Gall-bearing petioles of Nymphæa advena. a, The answer seems to be that it depends on the external views of the gall; the dotted circle marks the presence of oxygen in the deep "abyssal" part of the epidermal window, through which the adult emerges. b, lake, both for the whitefish and their food, the larvæ of the gall cut open, showing the larva of Hydromyza certain midges. confluens within...... 66 Very respectfully, Figure 23. The larva of Hydromyza confluens. a, side view of the whole larva; b, the caudal peritreme spine, greatly ALFRED C. LANE, enlarged; c, posterior view of the respiratory aperatures; State Geologist. d, the prothoracic spiracular apparatus, removed and enlarged (the mark close behind the mouth in the upper figure shows the location of this.) ...... 67

Annual Report for 1907 / Walnut Lake – Page 1 of 66 BIOLOGICAL SURVEY OF WALNUT LAKE, LETTER OF TRANSMITTAL. MICHIGAN. Sir:—I hand you herewith a report on the results of a BY THOMAS L. HANKINSON. biological survey of Walnut Lake, Oakland county, Michigan, by Thomas L. Hankinson and others. The principal object of the investigations upon which this INTRODUCTION. report is based was the determination of the reasons why the whitefish can live in Walnut Lake, so that a basis The present paper is the result of a biological survey of might be had to determine in what other lakes the Walnut Lake, Oakland county, Michigan, carried on species could be propagated. during the spring and summer of 1906, from April 3rd. to August 30th. The chief purpose of the work was to The zoological part of the report consists of six sections, obtain facts concerning the fish life, not only to find out as follows: what kinds of fish lived in the lake, but more particularly (1) A description of the different fish habitats in the lake, to learn as much as possible about the feeding habits, with a list of the fish found in each; breeding habits, habitat and environic (biological and physical) relations of the species. The work while thus (2) A list of the fish of the lake, with notes on the ecological, was also economic in nature, for if successful preferred habitats, food and breeding habits, and it should reveal some of the laws governing the economic importance of the species; occurrence and local distribution of the species studied, (3) A list of the animals of the lake, which have an and thus furnish evidence of the kinds of lakes in which influence upon the fish fauna; these forms may be planted most successfully. The investigation was made at Walnut Lake, primarily, (4) A summary of the data applying to the occurrence of because it was known that white fish live and thrive the whitefish in the lake; there. These fish have been planted in a number of (5) An appendix describing the apparatus used in the apparently similar lakes in the State by the Michigan aquatic work; Fish Commission, but for unknown reasons, have been unable to maintain themselves, except in a few (6) A list of the aquatic insects of the lake, with notes on instances. It was, therefore, hoped that a study of this their economic importance by James G. Needham. lake might lead to a knowledge of the conditions which enable the white fish to live there, and that this It will thus be seen that aside from the discovery of the information would be such that it could be used in the environmental conditions frequented by the whitefish in future work of stocking inland lakes of the State with this Walnut Lake, the report forms an important contribution fish. to our knowledge of the fish fauna of this lake, and of the habits of the species found there. Staff and collaborators.—The investigation was in official charge of the State Geologist, Dr. Alfred C. Lane. ALEXANDER G. RUTHVEN, Professor Jacob Reighard, one of the Zoological Chief Field Naturalist, Biological Survey of Michigan. Advisors of the Michigan Board of Geological Survey, ALFRED C. LANE, with Charles C. Adams, at the time Curator of the State Geologist. Museum of the University of Michigan, outlined the general plan of the work. Professor Reighard also gave much personal oversight to the investigations while they were being carried on. The field party was in direct charge of the writer, who devoted his time to the study of the fish life of the lake. In this he was aided for a part of the season by Messrs. Ellis Michael of La Porte, Indiana, and Elmer McDonald of Lerna, Illinois, as scientific assistants, and by Joseph Peters of Detroit, as fisherman. Mr. McDonald also acted as .botanical collector during his stay. The party was augmented from time to time by the following specialists, who spent limited periods working on special aspects of the problem: Prof. James G. Needham, Lake Forest University, Insects. Mr. Bryant Walker, Detroit, Michigan, Mollusks. Mr. A. Franklin Shull, University of Michigan, Insects.

Annual Report for 1907 / Walnut Lake – Page 1 of 66 Prof. N. H. Harvey, State Normal College, Fresh-water environmental conditions for fish. These stations were Sponges. visited as frequently as possible thereafter, and each was examined to determine its peculiar biological Dr. Charles A. Davis, Ann Arbor, Michigan, Plants. conditions, inhabitants, and other significant features. Dr. John Eastwood, State Hygienic Laboratory, Water The routine work in the field consisted principally of the Analyses. study of the conditions at the different stations, but no attempt was made to give all stations equal attention, the Acknowledgments.—I wish to express my thanks to the visits to particular stations being made when weather following persons who most generously assisted us in conditions were most favorable for observation, or when the work, by actual field work, by advice, or by identifying some particular specimens or facts were wanted. On specimens. Those who helped in the last named way account of the large size of the lake it was impossible to have the names of the kind of specimens determined for devote a large amount of time to each station, but this us following their names. difficulty was in part avoided, for as the season Jacob Reighard, University of Michigan, Ann Arbor, advanced it was noted that the established stations Mich. could be grouped under several major types, and study was focussed on type stations. A. C. Lane, State Geologist of Michigan. Besides the field work, much indoor work was C. C. Adams, University of Chicago, Chicago, Illinois. necessary, and specimens were taken to the temporary W. B. Barrows, Michigan Agricultural College, Lansing, laboratory for study, identification and preservation. All Michigan. specimens which could not be identified with certainty by members of the party were sent to various specialists for O. W. Caldwell, Normal School, Charleston, Illinois. identification, after being properly prepared. In the T. H. Briggs, Normal School, Charleston, Illinois. indoor work the fish were, of course, given particular attention. When the collections from the different F. S. Collins, Maiden, Massachusetts, Algæ. stations were brought in, the specimens were sorted, Ellen Bach, Ann Arbor, Michigan, Characeæ. those of each species measured and the larger ones weighed. Specimens of each species in the collection C. A. Davis, Ann Arbor, Michigan, Seed plants. were then opened, the sex organs noted, parasites G. N. Calkins, Columbia University, New York City, removed and preserved, and any food in the alimentary Protozoa. canal removed, examined, and saved for more detailed study. The study of the food removed from the fish J. P. Moore, Philadelphia, Pennsylvania, Leeches. furnished us with many clews to the habits of the various Ada Weckel, Portage, Wisconsin, Amphipods. fish, their habitats, their relation to other organisms, and economic importance. In the time available not much A. E. Ortmann, Carnegie Museum, Pittsburg, could be done toward making exact determinations of Pennsylvania, Crayfish. every substance found in the alimentary canal of every E. A. Birge, Madison, Wisconsin, Daphnia. specimen, even if this had been desirable in a general ecological survey of the fish life of the lake, such as was J. G. Needham, Lake Forest, Illinois, Aquatic insects. undertaken. The stomach contents were preserved, O. A. Johannsen, Ithaca, New York, Aquatic diptera. however, and have been deposited with the Walnut Lake Collection in the Museum of the University of Michigan, Nathan Banks, Washington, D. C., Spiders. where they can be more carefully studied. In many Bryant Walker, Detroit, Michigan, Mollusks. cases negative data concerning food were obtained, but these are usually not significant, especially where Alexander G. Ruthven, University Museum, Ann Arbor, collecting was done with the fyke-net or gill-net, since it Michigan, Amphibians and reptiles. is possible that digestive processes were active for many hours after the fish were caught. Allowance must also R. E. Richardson, Urbana, Illinois. A few sunfish and be made when examining the stomach content records minnows. of fish taken at a particular station, for the possibility of I would mention especially the financial assistance given the individual having obtained the material at some the party by Dr. A. C. Lane and Mr. Bryant Walker, for station other than the one where it was caught. which we are duly grateful, and the kind assistance of Maps.—The lake was carefully surveyed during the many of the residents near and about the lake. winter preceding the field work, by A. A. Adams, under Equipment and methods of work.—Full equipment was the direction of Professor Gardner Williams of the furnished the party by purchase, and by loan from University of Michigan, and the excellent map, (PI. 14), various institutions, and a small laboratory for indoor was based on this survey. A large number of soundings work was fitted up in a room in the farm house where the were made through the ice, and the bottom and shape of party secured lodgings. After the preliminary study of the basin of the lake was thus obtained. This carefully the lake and its surroundings, it was divided into a series prepared map was the basis for much field work, and of stations, or regions having peculiar sets of saved a great amount of time in the location of stations. Annual Report for 1907 / Walnut Lake – Page 1 of 66 A topographic map of the region around Walnut Lake the form of woodlots and uncleared swamps, to give was published by the U. S. Geological Survey, variety to the landscape, and to add to its attractiveness. cooperating with the Michigan Geological Survey* just The region to the north of the lake is higher and rougher after the field work for the season was completed. A than that immediately adjacent, and abounds in basins portion of this map is used as the base for the map of and depressions some of which are of considerable size the surface geology (Pl. 13). and contain lakes, swamps and bogs in various stages of development. It may be said, in passing that Walnut The soil map of the Pontiac area† was also of Lake lies near the southern border of one of the most considerable service in the reconnaissance of the picturesque regions to be found in Southern Michigan, country in the vicinity of the lake at the outset of the and, when its beauty is fully appreciated, is destined to work, and was used in compiling soil and vegetation become the summer home of a much larger number of data. people than now seek it. To the south of the lake the *The Pontiac Quadrangle. U. S. Geological Survey, Washington, D. country slopes gently, and a few miles south becomes a C., 1907. nearly flat plain, the geological significance of which is †Soil Survey of the Pontiac Area, Michigan. Bureau of Soils, U. S. pointed out below. Dept. Agriculture, Washington, D. C., 1904. The hydrographic basin of the lake is relatively small. Nomenclature and measurements.—For the benefit of There are only three small streams flowing into it, but the general reader, and to aid the publishers, common one of which is permanent, and that becomes very names have been used in the body of this report instead insignificant in August. These three streams all enter the of scientific ones, except (1) in the case of species for lake on its north side, one at the extreme extension which no common name could be found, and (2) in the (Station 26, PI. 15), and the others at the head of the lists of the flora and fauna. In the latter, both common wide bay at the northeastern end (Station 40, PL. 15). and scientific names are used, and the reader is referred Originally the lake had no surface outlet, but about 1896 to these sections when in doubt as to the scientific name an artificial channel was dug at the western end (Station of any species. 1, PI. 15), through a shallow valley, to a small stream In all records of the length of fish, the measurements which runs southeastward to the Rouge river, thus were from the tip of the snout to the tip of the caudal fin. lowering the surface level several feet. It was reported All measurements and weights are in American units, by farmers of the vicinity that there was no outlet from and temperature readings are in centigrade units. the lake whatever until this ditch was dug; it is possible that the water found its way out from the basin by percolation through porous sub-strata, as is the case PHYSIOGRAPHY AND GEOLOGY. with many lakes without outlets, but there is no known BY C. A. DAVIS. evidence of this. Location and description of Walnut Lake.—Walnut Lake At present, of the entire length of about three and one- lies in the southern part of Oakland County, Michigan, half miles of shoreline, but a half-mile along the west four and one-half miles south-southwest of Pontiac, shore, and about a quarter of a mile on the east side, are which is the nearest large town. It is a little more than a low and marshy. These marshes vary in width from a mile east of the line of the Detroit and Orchard Lake few feet to about three hundred, the widest part lying just Electric Railway, which gives direct connection between southwest of the outlet, covering a broad platform of the lake and Detroit, either by way of Pontiac, or more marl. There are two areas of firm marl shore, each quickly by way of Farmington Junction. More exactly, it about a fifth of a mile long, one on the south side and the is situated in the south half of Sec. 24, and the north half other along the straight part of the shore. The rest of the of Sec. 25, West Bloomfield Township (T. 2 N., R. 9 E.). shore is gravelly and more or less covered by bulrushes, It is rather more irregular in outline than is usual in lakes sedges, and similar grass-like plants, which flourish in of its class, and has a shore line about three and one- wet places, while in a few places the sod-forming half miles long. The longer axis lies east and west, and grasses of the surrounding cultivated and pasture lands is nearly a mile (in round numbers, 5000 feet) in length, come down to the water's edge, a condition which and its extreme width from north to south is a little more probably prevailed on a much larger part of the shore than three-fourths of a mile (more exactly, 4350 feet). Its before the water level was lowered by cutting the outlet. area is approximately 232 acres, or about one-third of a Between the shore and the deep part of the lake, as is square mile, and the greatest depth found by the shown by the contour map, Pl. 14, there is an irregular surveyors was 101.3 feet. Its surface lies at an elevation belt of shallow water less than 5 feet deep. This is 700 of 881 feet above sea level, as determined by the U. S. or 800 feet broad along the east side, but in some places Geological Survey, and is 306 feet higher than the along the southwestern and southern margins it is only a Detroit river. few feet wide. The bottom of these shallows is almost The lake is beautifully situated in a district where the entirely marl, which thus forms a platform almost around surface is gently undulating and mostly cleared for the lake, and, in the case of the marsh at the west end, farming purposes, but there are sufficient remnants of has actually filled a bay of considerable size. This marl the forest which formerly covered the entire region, in bottom has an admixture of sand in places, but is Annual Report for 1907 / Walnut Lake – Page 1 of 66 generally quite pure, and makes a firm, clean bottom. in the path of the ice, the resulting drift would be fine- From the outer edge of this shelf the sides of the lake grained and the soils clayey, while the boulders and basin are quite steep down to depths of from 30 to 60 pebbles would be chiefly limestones and shales, or feet, where the slope becomes more gradual to 75 feet, because of the soft character of these rocks, wanting, or and in a number of smaller areas to 95 or even more of more resistant materials brought from a greater than 100 feet. The location, relative size and shape of distance. If the Antrim shale and Monroe limestone, these deeper holes are accurately shown in PI. 14. both easily recognized, occur in quantity in the drift of the region north of their out-cropping over the Coldwater The bed rock.—As determined by the records of deep shale or Marshall sandstone, it is good evidence that the wells in the adjacent territory, the bed-rock in the vicinity ice which deposited them came into the locality where of Walnut Lake is rather uniformly about 300 feet, or a they were left, from the south. Such evidence is always little more, below the surface, rising from about 500 feet to be taken as incomplete, however, unless very definite, above sea level near Detroit to 750 feet just north of since the same rocks may occur in other directions in Pontiac, while the land surface rises from about 600 feet regions more remote, from which the ice may have to over 1000 in about the same distance. It has already brought them. been noted that the present surface rises much more abruptly after Oakland county is reached than in the Glacial geology of the region.—The last geological regions to the southeast, and the same is true in a lesser epoch before the present was the Glacial, during which degree of the rock surface, which forms a low, broad great ice-sheets pushed out from centers of ice ridge, 200 feet or more high, the axis of which runs accumulation in the polar regions and covered parts of northeast and southwest; this ridge had a marked what are now the temperate zones. In eastern North influence in determining the trend and location of the America, an ice sheet pushed out from the highlands of surface deposits. Labrador, and, at the period of its greatest development, extended across the basin of the Great Lakes as far The rock lying nearest the surface over most of Oakland southwest as the Mississippi river, covering the county is the Coldwater shale, a thick deposit of intervening regions, including Michigan. From this generally dark-colored gray, blue, red, or green, fine- farthest limit, the ice sheet slowly melted back, as grained, thin-bedded, soft rock, often called slates by climatic conditions ameliorated, and finally disappeared well drillers. In most places where it has been entirely, but the retreat occupied a very long time, and penetrated, it is found to be dry, or yields small was accompanied by many halts and small readvances, quantities of salt water. Below this is the dark-colored, only the last of which left legible records. If the following often bituminous Antrim shale, which is the bed-rock facts are borne in mind, the theory of glacial erosion and nearest the surface in southeastern Oakland county, deposition will be more easily comprehended. The and, immediately above it, is a light-colored, often movement of glacial ice is, in effect, a kind of slow coarse-grained, water-bearing sandstone—the Marshall flowage, as if the ice were a very stiff liquid, and as with sandstone—which is the rock nearest the surface in the other liquids the rate of movement is swifter where the extreme northwestern corner of the county. Full slope is steep and the mass deepest. Where the rate of accounts of these formations will be found in the various flow is greater than that of melting the ice advances, publications of the Michigan Geological Survey. where less it retreats, and when the two are equal, the Below the Antrim shale, and forming the upper stratum ice margin is stationary. The ice in its passage over the of bed rock farther to the south, are the limestones of land surface removed, from the underlying rocks, the Devonian and Silurian ages, with sandstones among soil-covering resulting from the action of the agencies of those of the earlier periods. The chief interest in the rock-disintegration through previous ages of geological bed-rock lies in the fact that from it a large amount of the time, broke away, rounded, and pulverized fragments of material which constitutes the present surface deposits these, and generally planed and polished the surface of has been derived. These deposits are glacial drift, and, the parts left. A large part of this eroded material, as it is estimated that from 50 to 90% of such drift was including fragments of all sizes, was picked up by the gathered by the ice from within a few miles of the places ice, incorporated in it and transported for greater or less where it was laid down, it will readily be seen that there distances, and then dropped wherever the ice melted. is an intimate relationship between the bed rock in the Much of the included material was carried to the margins region passed over by the ice and the soils of the region of the ice, since these were the chief areas of melting, of deposition. Moreover, a comparative study of the and there piled up as accumulations which generally mineral constituents of the soil, especially of the larger took the form of lines of low, rounded hills, known as rock fragments, and the rock formations of the adjacent terminal and marginal moraines, or of flat sheets, with regions, gives an accurate means of finding out the more or less undulating surfaces, called ground direction of ice-flow. Thus, if the ice moved across moraines or till plains. In these moraines all kinds of sandstone areas, it would be expected that unmodified material from the entire region traversed by the ice are drift of the regions of deposition would be sandy, and the likely to be present, and, because of the transporting soils formed from it rather poor in plant food and coarse power of the ice, it has taken the form of a mixture of in texture, while the larger rock fragments would be of fragments of all sizes, from the finest clay to huge sandstone; if shales and limestones were the chief rocks boulders, but with the finer material predominating. This

Annual Report for 1907 / Walnut Lake – Page 1 of 66 material is technically called till, while the whole deposit, gravel and containing numerous lakes, is a well-marked sorted and unsorted, left by the ice, is called glacial drift. and characteristic line of glacial drainage, along which the waters of the melting ice of the two closely opposed In moraines of marginal types, and less frequently in the lobes of the ice sheet found an outlet to the southwest, ground moraines, were frequently included detached thence to the Mississippi valley and the sea. The sands masses of ice, sometimes of large size, which, becoming and gravels of the area are glacio-fluvial deposits left by buried in mineral debris, persisted for a longer or shorter this drainage, as the force of the streams and their time after the main mass had melted away, and, finally carrying power decreased. The lakes and swamps of disappearing, left more or less steep-sided depressions, this drainage area are located chiefly in basins left by the which, later, became lakes. The water from the melting melting masses of ice which had become detached from ice, flowing both within and without the glacier, carried the main bodies for some reason, and persisted for a with it suspended mineral matter, which was deposited sufficient time to become partly buried by the materials in places where there was slackening of the current, to which the outpouring streams from the main ice masses form more or less extensive areas of gravel, sand, or piled around them. Several miles to the north and even finer material, along the channels which the water northwest of this drainage region is a broken tract of followed. These deposits were most frequent and country which was apparently the place where the extensive on the morainal slopes away from the ice margins of the two lobes came together more closely front, and along the valleys in which the water from the still, and the records of each have been partly obliterated melting ice ran, and are known as glacio-fluvial deposits, by the outwash (as the debris-laden waters are termed) and, since they were formed outside the ice, or near its from both. This complex region is succeeded still farther borders, are important aids in showing the direction of north and northwest by the bold and prominent moraines the movement and retreat of the glacial ice sheet and its of the ice lobe from Saginaw Bay. lobes. *See report on Surface Geology, preceding this paper in this Annual Since the ice moved more rapidly in the deeper parts Report for 1907. these became the axes of movement, and pushed out farther from the centers of distribution than the thinner A mile to the south of Walnut Lake is another but much areas; thus the ice sheet had a scalloped margin, and, in less extensive line of glacial drainage marked by a flat later stages, was divided into lobes or tongues, the belt of sandy soil, about a mile wide, extending northeast marginal moraines of which were roughly concentric, and southwest on the south side of the morainal tract in forming a series of belts, one inside the other back to the which the lake lies. On the south side of this is a narrow last strongholds of the ice. It seems probable that the morainal tract which marks the halt of the ice front, while ice was always thinner on the highlands than in the the sandy area was the line of outlet for the water adjacent valleys, hence disappeared first from the discharged from it. This drainage valley is less former, while the latter still remained local centers of complicated in structure and relations than the one to the movement.* north, since it received the water from but one ice margin, but otherwise it exhibits the same characteristics The valleys now occupied by the Great Lakes were such and, because of its simplicity, is less difficult to study. Its centers of movement, and each of them has a series of course is also marked by fewer and smaller depressions, moraines more or less parallel with the margins of the of which Wing and Gilbert lakes are the most extensive. present basins, extending in constantly widening lines as they are crossed from the newer to the older ones over A short distance southwest of Walnut Lake is a nearly the region adjacent to them, until they meet in confluent flat, clayey district of less than ten square miles in area, masses known as interlobate moraines, i. e., moraines which has the chief characteristics of a till plain. This formed by the margins of two lobes when they were forms a recess in the moraine with which it is connected close together, or in contact. Thus the ice which and is an area in which the glacial debris was deposited covered the region which lies about Walnut Lake, in the in a nearly flat sheet, possibly from thick or resistant ice latter part of the facial period at least, since this is the which persisted longer than that on either side of it. part which left the clearest record, had its primary center About three and one-half miles south of the lake, after of movement in the Labrador highland, but came into crossing the drainage valley and attendant moraine, the this immediate locality from the southern part of the characteristic forms of glacial deposition abruptly basin in which Lake Huron now lies, and eventually disappear, and the country becomes monotonously flat, melted back into it. At the same time the country beyond with only occasional low, symmetrical ridges of sand and Pontiac, a few miles to the north, was covered by ice, gravel running for long distances across it. The highest also from the Labrador center, but coming immediately of these ridges lies just south of, and extends along the from the northern end of the Lake Huron basin, pushing border of, the hilly country, and others, which are more out to the southwest through Saginaw Bay. prominent, run more or less parallel with it, as the slope The topography about Walnut Lake, with its irregular towards Lake Erie is traversed. lines of low, rounded hills, numerous, undrained or These ridges are the shore lines or beaches of a series poorly drained hollows and swampy valleys is typical of lakes which existed towards the end of the Glacial morainal topography of a rather simple kind. The region period, between the front of the retreating ice and the to the northwest, covered by great masses of sand and Annual Report for 1907 / Walnut Lake – Page 1 of 66 highland which had recently been abandoned by it, the glaciated regions from the country south of the Ohio water from the melting ice rising to such a height as was River, in which they had passed the long period of the necessary to find an outlet to the sea, either around the ice invasion. edge of the ice or across some gap in the moraines. To particularize still further and apply the principles laid The ice sheet persisted somewhat longer in the east, in down above to the immediate district under southern Ontario and in the St. Lawrence valley, than it consideration, the moraine in which Walnut Lake lies is did in its thinner western extension, and hence the early known as the Fort Wayne moraine, and extends from the outlets of the lakes mentioned above were to the city in Indiana near which it was first studied, and from southwest, ultimately through the Mississippi valley. The here has been traced around the lake Erie basin. This level of their outlets, or spillways, as they are sometimes moraine is one of the last well-marked moraines formed called, fixed the height to which the waters of the lakes by the Huron-Erie lobe of the ice sheet, before it shrank rose, and the length of time for which they served to back to the low lands about the deeper part of the areas keep the water at a given level, if other things were now occupied by Lake Huron and Lake Erie. The basin equal, determined the strength or prominence of the of Walnut Lake is a morainal depression, and while it is resulting beaches. Thus it is fair to assume that well- of rather irregular form for a morainal lake, and has the marked beaches are the result of a much longer period outline often seen in lakes occupying drowned valleys, it of action than low and faint ones. seems most probable that it is the mold of an unusally These old shore lines of the glacial lakes may be formed detached mass of ice, which was wholly or partly recognized by their close resemblance to shores of the buried in the moraine by the mineral matter included in present lakes, and consist both of cut shores, where the glacier, so that it persisted until after deposition had waves and currents washed away the materials against ceased, and, later, slowly melted away, leaving a basin which they struck, and of built shores, those on which with steeply sloping sides, which immediately filled with the waves piled sand and gravel into long, low, usually water, since much of it was below the level of any outlet smooth-topped ridges, very narrow in proportion to their channel and the ground water table as well. length. The highest glacial lake is known as Lake Post-glacial history of the region.—After the retreat of Maumee, and three fragmental shore lines from about the ice the recently abandoned surface of the glacial 800 feet down to 760 feet above sea level are attributed deposits was subject to weathering, rainwash, cutting to this lake. The next stage below this was Lake and erosion by streams, until such time as it was Whittlesey, with a nearly continuous beach about 740 protected against such deformation by the growth of feet, and the lowest one within the limits of the area vegetation dense enough to cover the loose surface and mapped was Lake Arkona, which formed a definite shore check erosion. The surprisingly small amount of line about 40 feet below the last. The position of these evidence of such change of the form by erosion in glacial important ancient shore lines in the Walnut Lake region deposits of the vicinity may be taken as an indication of is shown on the map, Plate 13, together with the names either different climatic conditions from those existing by which they are known. now, for a time after the ice retreat, so that erosion did The relationship of this phase of geological history to not proceed on the same scale as at present, or of the present day conditions and especially to the animal and rapid covering of the steep, soft slopes of the moraines plant life in Walnut Lake is plain, when it is understood by plants. that the drainage of the region at the present time is The latter seems a strong possibility, since forests of largely controlled by the ancient lines of drainage, and trees of large size, with a dense undergrowth of lesser that the modern streams find their way to the sea plants are reported by Russell1 as growing not only through valleys formed by the glacial streams or by the around the moraines bordering the Malaspina glacier in outlets of the glacial lakes; these valleys and streams Alaska, but on the debris-cove red margins of the ice are known to be the lines of migration through which itself. If similar conditions existed around the border of many species from the valley of the Mississippi have the greater ice sheet towards the close of the Glacial found their way into the Great Lakes and their tributary Period, it is not surprising that the present slopes of the streams. In cases where the connection is not a direct moraines do not show more considerable evidences of one, as where two streams flowing in different directions erosion by wash and weathering, because they do not occupy an ancient valley, as frequently happens, the erode if well protected by forests or other types of divide between the two is commonly a swamp, in which, vegetation. If some agency had not prevented erosion in times of flood, there is a complete water connection the slopes would have been much flattened, the valleys from one stream to the other, so that fish and other would show much greater cutting, and the drainage aquatic animals pass as freely over the divide as if it did systems of the streams would be much more completely not exist. developed than now, since, if the slopes had been bare It is then important, in considering the origin of our long, storm-waters would have rushed into the valleys Michigan lakes, to take into account also the past history and created torrential conditions and very rapid stream of the region, and especially the glacial history, since this cutting. The fact that in the adjacent country there has undoubtedly had much to do in establishing possible been extensive gulleying of cleared slopes in the routes over which species of animals returned to the comparatively short time, less than a century, that the

Annual Report for 1907 / Walnut Lake – Page 1 of 66 region has been under cultivation, is to some extent a other Michigan lake known to the writer would it be more confirmation of the hypothesis that these slopes were easy to attribute the formation of marl deposits wholly to not long in being covered by vegetation after they were mollusks than in Walnut Lake, because of the vast left by the glacial ice. numbers of dead shells of certain species of snails which are heaped up on the shores of the lake (Pl. 26). The Because of the small erosion of the surrounding slopes presence of extensive beds of the stonewort (Chara) in and the lack of tributary streams, the basin of Walnut various parts of the lake, associated with other lime- Lake was not modified by mechanically deposited secreting Algae, and the abundance of the characteristic material from the higher lands around it, nor was a remains of these plants in the marl, much exceeding natural outlet ever developed, either by overflow from those of the shells, point to the real origin of the beds the lake itself or by the cutting back of the valley with here, as elsewhere. The occurrence and approximate which the lake is now connected by a ditch, as might extent of the marl beds along the shores of Walnut Lake have been the case if the drainage of the area had been have already been indicated on another page, but it more strongly developed. The feebly developed should be noted here that the size of the original basin of drainage in this vicinity must have had its direct effect the lake has been decreased by just so much space as upon the fauna of Walnut Lake, by keeping the fish and these beds occupy. A full discussion of the formation other wholly aquatic animals in the lake land-locked, and uses of marl will be found in a former report of this except in unusually high water, when temporary surface 1 Survey. overflow from the lake may have found its way through the present outlet valley to the established stream The marl beds furnish shallows with a firm, clean bottom system with which the lake is now artificially connected, upon which but little vegetation grows, and of a texture but never for a sufficiently long time for a channel to be sufficiently coarse (about that of sand) to be adapted to cut down to the usual level of the lake. use as spawning beds for some species of fish; that they are used as such will be seen by reference to the This land-locked condition of the lake has prevented free descriptions of the stations on a subsequent page. migration of fish and other aquatic types into and from it, except at what must have been rare and very brief 1Geological Survey of Michigan, VIII, Part 3, Lansing, 1903. intervals, since longer ones must have inevitably opened up a permanent outlet as the texture and composition of Peat.—But little filling has been done by peat at Walnut the drift makes it very easily cut by water-courses when Lake, and, so far as observed, the deposits of this once these are established, as is to be seen along the substance are all superficial, being confined to those present ditch. parts of the lake where the marl beds have nearly reached the surface. The beginnings of peat deposits Since the ice block melted from it the basin of the lake may be seen, however, in the accumulations of plant has been slightly increased in superficial area by the remains as black mud, noted in the descriptions of the action of waves, wind formed currents and ice-shove in stations. The marshy tract at the west end of the lake winter, and the material removed by these agencies has has considerable peat above the marl, and seems to either been spread over the sides and bottom of the have been formed by the growth of much the same basin, or, in the case of the ice action, pushed back from plants, the bulrushes and other shallow water types, as the shore in the form of a low ridge just above the water- are seen in the shoal water at the present time, and as line. are now growing upon the marsh. Peat is formed in

1 large quantities in the lakes of Michigan, and has Russell, I. C. Second Expedition to Mt. St. Elias in 1891, U. S. G. S. Report, XIII, 2, p. 76. converted great numbers of the smaller ones into bogs and marshes, but lakes like Walnut Lake, which have Marl.—On the other hand, internal agents in the form of considerable deposits of marl, seldom have much peat plants and animal organisms have been engaged in until late in the history of the transition from lake to filling the basin, and have decreased its surface much marsh. An extended discussion of the formation of peat more than the others have increased it. The chief has recently been published in the annual report of the modifying agent is marl, which is, when pure, a Michigan Board of Geological Survey.2 yellowish-white, more or less powdery or granular 2 substance, often appearing like white clay, and Davis, C. A. The Ecology of Peat Formation in Michigan, Report Mich. Geol. Surv., 1906, p. 94. composed of nearly pure calcium carbonate. Marl, or "bog lime," as it has been termed, is precipitated from Human agencies.—In recent years the lake and the the water of the basins in which it is found by a number conditions about it have, in various ways, been of organisms, both plant and animal. Of these the plants profoundly modified by the hand of man. The clearing belonging to the stoneworts (Characeæ), and the blue- away of the forest from the surrounding slopes give the green algæ (Cyanophyceæ) are by far the most winds much freer access to the water surface and important agents, while of the animals, the mollusks increases evaporation, and the action of waves and contribute the largest amount. The marl usually contains currents along the shores during the season of open sufficient unbroken shells of mollusks to attract attention, water, as well as blow the finer soil particles into the so that formerly the entire formation was supposed to be lake. At the same time a much larger proportion of the made up of shells, and was called shell-marl. In no water which falls upon the drainage basin finds its way

Annual Report for 1907 / Walnut Lake – Page 1 of 66 immediately into the lake, bringing with it the finer parts have been made, it is probable that it is made up of of the material obtained by erosion of the denuded land slightly sorted rock debris, which may be irregularly and surface, in the form of mud and silt, and this material incompletely stratified. spreads itself along the shores and over the bottom, 1Soil Survey of the Pontiac Area, Michigan. U. S. Dept. Agriculture, making the water less clear and pure after a storm than Washington, D. C., 1904. when the region was forest-covered. Physiographic features of the lake shores.—In the It is evident also, that the silting up of the lake will go on present paper it is not possible to go into details more rapidly under present conditions than formerly, but regarding the building of the various types of shore on account of the small drainage area directly tributary to formations to be seen along the shores of such a lake as the lake, the porous surface deposits around it, and the Walnut Lake, but it may be mentioned that quite a small size of the streams flowing into it, this change is of variety of such formations occur on a small scale, and slight significance. The artificial outlet, which is now a are chiefly the result of the action of ice during winter permanent feature of the lake, is of more importance, and spring, of the waves formed by the winds, of surface since it has materially lowered the surface of the lake, currents along the shores, and of plants and animals. and decreased its superficial area. Moreover, this change must also affect the biological relations of the The primary surface currents at any time are in the same lake to whatever extent the opening of a passage for the direction with the wind; and as they are due to the drift of free inward and outward movement of aquatic plants and the surface water before the wind, the latter tends to pile animals will affect the balance of life which was up the water on the lee side of the lake, from which it established before the outlet was made. returns along the other shores by gravity, in its passage cutting off the ends of any points upon these and forming Soils of the drainage basin of Walnut Lake.—The spits and bars in bays behind the points, or depositing morainal deposits about Walnut Lake are chiefly made the finer and lighter drift-material in the still waters of the up, on the surface at least, of a gravelly or sandy loam, bays. These facts account to some extent for the containing a considerable number of boulders and deposits of fine mud in all of the bays mentioned in the smaller rock masses. This upper layer with its contained descriptions of the stations on a subsequent page, and organic matter makes up the soil, and the type found for the sand spit at station 41, described beyond (page here has been named the Miami gravelly loam in a 189) and shown in Pl. 43, although direct surface current report of the Bureau of Soils of the U. S. Dept. of 1 and wave action, as shown in plate 43 are perhaps the Agriculture. This type of soil covers practically the primary causes of the formation of this spit, and the whole drainage basin of the lake, except at the direct action may always be considered as important in southwest side, where a somewhat finer type, the Miami all cases. The combined effect of waves and currents sandy loam, and at the south, where a considerable tract upon the shores is, therefore, to straighten them by of coarser material, the Marshall gravel, occur. These eroding the points and filling the bays, the latter process types entirely surround the lake and cover most, if not greatly hastened, in many cases, by submerged plants, all, of the area which can be considered tributary to it, which retard the moving water, thus causing suspended and are sufficiently porous so that they absorb a matter to drop near or on them, and act as direct considerable part of the rainfall, which percolates to the contributors to the filling by their growth and decay. ground water level and finds its way out into the lake. The finer particles of these soils and of the underlying till The erosion effects mentioned may be seen on the ends are, in considerable part, fragments of limestone, hence of any point exposed to the action of waves and the percolating water becomes strongly impregnated currents, in the coarseness of the material upon them, with calcium salts, the carbonate predominating, and, and in the evidences of removal of the end of the point, finding its way into the lake through subsurface springs, which will usually have a prolongation of considerable is the chief source of the marl. The water draining length, extending lakewards below the surface of the directly into the lake over the surface is likely to contain water. Such washed shores afford excellent breeding much less dissolved mineral matter, since it does not places for several species of fish, as noted elsewhere. remain long-enough in contact with the rock particles to After westerly winds, accompanied by showers, the become mineralized. westward returning currents along the north side of Walnut Lake could be traced for more than a quarter of a The surface of the drainage area of Walnut Lake is, mile by the muddy water from one of the inflowing then, of such porous types of soils that little water runs streams. This water instead of flowing out into the lake, away on the surface, most of it becoming-part of the as would have been the case but for the existence of the ground water, and hence a relatively small area serves current, was turned westward immediately at the mouth to keep the water of the lake high, and the clearing and of the stream and formed a well-marked belt, a rod or cultivation of the land has not affected its absorbing more wide, in the clear water of the lake, and flowed with power as much as frequently happens in more compact considerable rapidity, even though no wind was blowing and clayey types, where the soil, after clearing, permits at the time when the observations were made. very little water to soak into it. Little is known of the structure of the glacial drift of the locality, below the soil It is apparent, also, that these currents in shallow water line, but from the conditions in other places where cuts must move the finer organic debris along the bottom until

Annual Report for 1907 / Walnut Lake – Page 1 of 66 bays are reached, when this material is swept into them weed zone, and that part of it which was adjacent to the and left as sediment in their quiet water, and in such shoal was included in the station in all cases, on account places of accumulation conditions sooner or later of its close relationship to it. The following stations were become favorable for the growth of plants, and these, in of this type: 3, 23, 49, 37, 46, 36, 16, 12, 6 and the turn, hasten the process of filling the bay. After the central part of 4. plants become established, the bays furnish a favorite (2) Firm shore type.—In stations of this type the water habitat for some of the most important food and game conditions were similar to the last, but the shore was fish of the lake. high, firm, grass-covered, and without a sedge zone; From the consideration given above, it seems that many frequently also there was a narrow beach between the factors, not always taken into account, may enter into water and the shore vegetation. This type included the problem of explaining biological relations in even so stations 11, the eastern part of 19, 27, 45, and 44. small a lake as the object of this study, and that logical (3) Bulrush-covered, shoal type.—Stations of this type relations in even so small a lake as the object of this differ from type 1 only in having a conspicuous growth of study, and not only must the present history be studied, bulrushes on the shoals. It includes stations 15, 35, 24, but also the past, for there may be important matters 20, and the western part of 19, and the northern part of overlooked if this is not done. 4. (4) Swamp loosestrife-fringed type.—In this type, the FIELD STATIONS. shoals had black bottom soils arid abundant luxuriant BY T. I. HANKINSON. aquatic vegetation, including a water-lily zone. The shallow water on the shoreward border had a distinct In order to be able to attack systematically the problem fringe of swamp loosestrife. There were but two stations of the relation of the fish life to the environment, stations of this type, 31 and 26. were established where different environmental conditions prevailed, and these places were subjected to (5) Marsh bay type.—This type included two small bays careful study. The stations were located early in April, with very abundant aquatic vegetation, and a shoreward before the aquatic vegetation had sprung up, to that in border of sedges and bulrushes growing in several some instances after the vegetation appeared minor inches of water. From each of these bays a ditch differences were observed within the station areas first extended back into the adjacent marsh. Stations 7 and located. In such instances the smaller areas were 41 were the only ones of this type. designated as substations. It is hardly necessary to (6) Bulrush shoal type.—The extensive area of shallow state that the boundaries of the stations were rarely well water between the island on the east side of the lake defined, but merged gradually into each other. and the main shore, constituted station 54, the only one The stations were located at the beginning of the field of this type. The bottom, of this area was densely season, after a careful preliminary examination of the covered by bulrushes, flags, and many other species of lake and its surroundings, during which many sample plants. collections were made. The following characteristics (7) Swamp shore type.—Station 40 was the only one of were the chief ones taken into consideration in locating this type. It was peculiar in having a wide swamp along stations: (1) aquatic vegetation, (2) nature of the bottom, the shore, and a broad shoal with an abundant growth of (3) depth of the water, (4) nature of the soil of shore and aquatic plants, forming complex associations. bottom, (5) topography of shore and bottom, (6) shore vegetation, (7) exposure to waves and winds. (8) Outlet head.—This station included the first thirty or forty feet of the outlet, or that part of it in which lake Since collections and observations were made over the conditions were prominent. greater part of the lake, a large number of stations were established, the general location of which can be seen in (9) Deep water type.—This type comprised all stations at Pl. 15. The head of the outlet (the landing place) was which the water was over thirty feet in depth. The station 1, and all stations along the shores of the north bottom was usually soft and oozy, and there was little, if half of the lake were given even numbers, while odd any, except microscopic vegetation. Stations numbered numbers were used along the south half. The stations at from 200 to 250 were of this type. some distance from the shore, in water over 30 feet deep, were given numbers between 200 and 250. BARREN SHOAL TYPE. The stations may be classified roughly under nine types Station 23 is a good example of the barren shoal type. as follows: It extended for about a quarter of a mile along the south (1) Barren shoal type.—In stations of this type the shore, just west of the entrance to the bay. In this shores are low, sedge-covered, and often marshy, and station were included the woods bordering the shore as are replaced off shore by a shallow shelf (known as the well as the zone of pond-weeds which marks its shoal) which is broad, and has a bottom of pure marl, or lakeward border, for the reason that they probably marl and sand, and only inconspicuous vegetation. At determine, to a considerable extent, the fish fauna of the the outer edge of the shoal there was usually a pond- shoal. Altogether the station had five zones (of which Annual Report for 1907 / Walnut Lake – Page 1 of 66 three were terrestrial) with peculiar environ!c conditions. low point of the beach mentioned above, the bulrushes These zones were as follows: (1) the timber zone, (2) formed a thin growth over the entire area, while the wet the sedge zone, (3) the beach or shore, (4) the barren soil had numerous plants of Chara, and of a small pond- shoal, and (5) the pond-weed zone off shore. weed with broad leaves, growing upon it, the vegetation thus being very similar to that of the adjacent shoal. The The timber zone was the remnant of the former forest soil of the beach was composed of marl, small fragments cover, and occupied an untillable portion of the bank of and gravel, sometimes thoroughly wave-sorted, and in the lake, partly swamp and partly steep slope, and was places of mixed small boulders and cobble stones (see less than a hundred feet in width. The tree growth was plates 16 and 17). The only part of the beach where sharply limited towards the lake by a ridge formed by ice animal life, which could be counted as a source of food shoving the soil back from the shore during its supply for fish, was at all abundant, was the low, wet, expansions in winter, and possibly also by the water in east end. Here during the latter part of August many spring. Evidence of the effects of the ice movement is young green frogs were seen, while tadpoles were shown by the inclination away from the lake of many of common in the shallow water near by. The dry part of the young trees on the shoreward border of the woods, the beach seemed to have few inhabitants except small as is shown in Pl. 16. flies, spiders and toad-bugs, but it was often visited by The chief effect which the tree zone had upon the fish the killdeers and the spotted sandpipers and life of the lake was in harboring insects which may occasionally by a yellow-legs. furnish a considerable amount of fish food. In the latter The shoals proper averaged about 100 feet in width out part of April, for example, adult midges, whose young life to where the water reached a depth of four or five feet, at stages are passed in the lake and form a large part of which depth it merged into the zone of dense pond- the food of the white fish, as well as other species, were weeds; it was broadest at the east end, where it was 200 present in dense swarms in this wooded area, while they to 300 feet wide, while near the center it was not more were nearly absent from the more open places. It is than 60 feet. In this zone the bottom is covered with probable also that other insects, breeding and marl mixed with sand, gravel, and small cobble stones. developing in the trees, are at times blown into the Sand was abundant on the western part of the shoal, water, where they are taken by the fish. where the bottom is quite hard, while the gravel was The sedge zone extended the entire length of the more uniformly scattered over the east half (Plates 56 station, covering the shore from the high water level to and 57). the woods, and even invading them to some extent. There was little noticeable vegetation in this area, During the late summer months the water receded from although during the summer the bottom was covered the lakeward margin of this zone leaving it bare. The with the stonewort which grew an inch or so high. conspicuous plants of this area, besides the sedges, Bulrushes were scattered over the entire shoal, and were a species of horse-tail and the common lake increased in abundance towards the end of the season. bulrush; the latter was common at the east end of the They did not, however, form a distinct zone, although a station, encroaching on the beach, which was here low tendency to do so was shown by the denser patches at and wet (PI. 17). Grasshoppers were abundant in this the east and west ends and the poorly defined one near sedge-covered area in late summer, and the plants the center. The fauna of this shoal was large compared served as resting places for the adult stages of a number with that of the others, and the presence of pebbles and of aquatic species, thus making the zone a source of small stones on the bottom seemed to furnish favorable food supply for the fish inhabiting the waters of the conditions for the inhabitants. Under these, numerous station. crayfish excavated hollows indicated in the small heaps of soil which they left in front of the holes. The stones The beach was a narrow zone between the water and also served to shelter many flat-bodied larvæ of the the sedge zone. It was bare during periods of low water, Mayfly (Heptagenia sp.), leeches, masses of leech eggs, especially during the latter part of summer, and was planarians, and small crustaceans. Three species of most distinct in the eastern half of the station (Pl. 17), fish, the Johnny darter, miller's thumb, and blunt-nosed although at the eastern end for a short distance, the minnow also placed their eggs on the under sides of flat shore was low with shallow pools of water scattered over stones in this area, as has been noted in the discussions it. In general, however, the beach was well above lake of these species on subsequent pages. During late May level, and had an evident slope to the water. Along most and early June, schools of blunt-nosed and straw- of the zone, plants of the sedge zone were advancing colored minnows, the former predominating, were towards the water by means of their underground stems, common over this shoal, especially at the eastern end, and but for the violence of the waves created by north where there was a considerable area of water only two and northwest winds, the entire beach might be covered or three inches deep. Some individuals of this species by vegetation. During times of strong wave action, were noted at all times where the bottom was gravelly, however, sedge plants were frequently found in the but they were frequently absent from the places without process of being washed out, and where a dense growth stones. Perch also were often seen in this area, reached the water, masses of plants were often torn especially at night, possibly searching for crayfish, which loose and moved along the shore by the waves. At the are chiefly nocturnal in their habits. The other species of Annual Report for 1907 / Walnut Lake – Page 1 of 66 fish seen here were the black bass and sunfish, which especially grasshoppers, live in the sedge zone, and, were frequent in the latter part of May and early June, falling into the water, become available as fish food. The and the blue-gills, which used the deeper places for relations of the shore zones at this station are shown in nesting. Two very different types of animals were Plates 19 and 20. The shoal out to a depth of four or sufficiently abundant near the deeper lake ward margin five feet, was about a hundred feet wide at the widest of the shoal to be mentioned, viz., a large freshwater part, but was much narrower in other places. The mussel, or clam, which was especially common near the bottom of the shoal was marl, with a little gravel in the pond-weed zone, and a colonial protozoan, Ophrydium shallower places, and supported little vegetation, except versatile O. F. M., which at times completely covered the the small form of stonewort found at station 23. The only bottom of parts of the shoal, with large, greenish, other exception was a small patch of bulrushes at the gelatinous colonies. east end, which enlarged as the season advanced, and was called substation A. The animal life was not as abundant on this shoal as on the south side of the lake, but leeches and amphipods were taken, and in the middle of April pupæ of the midges were very abundant upon the water surface, while the Iarvæ of the same insect were often dredged from the shoal bottom. On August 6 many small univalve mollusks were seen near the shore in very shallow water (but a fraction of an inch deep). These proved to be Limnæa desidiosa Say, and were the only living snails found in numbers away from regions of Whenever this shoal was visited air and water abundant vegetation. Minnows and other small fish temperatures were taken, the latter in several places were often seen here in April, but were less common where the water was about a foot deep. The readings later in the season. The following species were taken on are given in the table above, and they are too few to be April 28, when fish were noticeably abundant: Johnny of much value for purposes of generalization. darter, blunt-nosed minnow, black bass (young) and Etheostoma iowæ. Late in the spring there were times While pond-weeds were scattered over the entire when there would not be a single fish on the entire aquatic part of this station, and, as mentioned above, shoal, except at substation A, where perch, sunfish and stunted plants even occurred above the low water mark bass were usually seen. It was evident, at all times, that at the east end of the beach zone, in no place did they this patch of rushes had more attraction for the larger form a considerable growth in water shallower than four fish than the part of the shoal at the west end. The or five feet. In midsummer the shoreward margin of the accompanying table gives temperature readings at this pond-weed zone was indicated at the surface by station. numerous emerged flower spikes, while lake ward the zone was limited to a depth of water less than 25 feet, and no plants were found below that depth. The width of the zone varied with the steepness of slope of the bottom, from 100 feet near the ends, to 20 to 25 feet near the middle. Fish were common in this habitat at all times, as frequent examinations with the water glass showed. The most abundant species was the perch, which was especially numerous in June, when large Station 49 is a third example of the shoal type. It lay schools of them were noted here. along the southeastern shore, and included most of the broad peninsula and the bay adjacent to it on the east. Station 32 is of the same type as the one just The shore was low, and covered with sedges both on described, but was located on the north side of the lake. the wet and dry parts, although the sedge zone It extended east from the north bay for about a third of a disappeared abruptly at the edge of the high ground, a mile, to a point where the shoal becomes very narrow hundred or more feet from the water. This area was and the shore turns abruptly to the northeast. As in very similar to the sedge zone at station 32. The soil station 23, there was a broad sedge zone, and, in was of the same sandy character, and there were, along seasons of low water, a distinct broad beach. The the shore, small, shallow bays, in which the water was sedge zone terminates landward at the foot of a low bluff an inch or so deep. The shoal was broad, and covered which is tree covered, forming a lakeward edge of a with gravel and sand (Plate 21). The minnows and other woodlot (Pl. 18). These woods in spring were the small fish were generally abundant here, appearing in gathering place for great swarms of adult midges. At large schools in the shallow bays, where the high water, plants of the sedge zone grow down into the temperature was much higher than in the adjacent margin of the water, but at the low water period there is waters of the lake. As nothing could be found in these a broad strip of pebbly beach mostly without vegetation. bays which might serve as food to attract these fish, it As noted in connection with station 23, many insects, seemed probable that they were drawn to them by the

Annual Report for 1907 / Walnut Lake – Page 1 of 66 warmth of the water. On May 22nd, the following uniform growth of sedges, which grew during the early species were taken in a small seine hauled through the part of the season, at least, in shallow water. This shoal towards the mouth of one of the bays: 105 blunt- station as seen from the northern end is shown in Plate nosed minnows, 93 straw-colored minnows, 29 barred 23. killifish, 10 Johnny darters, 2 golden shiners, 2 least In mid-April the pike used this marsh as a spawning darters, 1 miller's thumb, and 1 Etheostoma iowæ. ground, and a little earlier a school of blunt-nosed This shoal was further used as a nesting place by the minnows were seen here, 200 feet from the main lake, Johnny darters and blunt-nosed minnows. which is the farthest point from open water where minnows were found during the season. Leopard frogs Station 46 extended along the northeastern shore of the were numerous, and great numbers of their eggs, and lake, from station 54 northward almost to station 40. Its later their tadpoles, were seen here. The marsh was a features were entirely distinct from those already favorite resort for insects, and for several days, described, in having no tree zone and no extensive beginning April 19, midges swarmed over it by millions, beach, while the sedge zone was a wide marsh, and the especially near the lake margin. From a distance they shoal very broad (more than 700 feet in places, see appeared as a cloud hanging low over the marsh, and Plate 22). The shore line was broken by a number of closer examination showed that the stems and leaves of small coves with hard, sandy bottoms, and water but a the plants were blackened by resting individuals. Plates few inches deep. Between the coves were narrow, 24 and 25, showing groups of these insects on a fish sedge-covered points. house near the edge of the marsh, will give some idea of In April and part of May large number, of minnows and their abundance in this habitat. The shoal area of this other small fish resorted to these coves and the station averaged less than 100 feet in width, and its marl shallower water of the shoal, but after the beginning of bottom supported very little vegetation, except a few thin June very few fish were found here. About the middle of patches of bulrushes which appeared late in the season, April the following species were collected here: blunt- and limited areas of small stoneworts. Almost daily nosed minnows, straw-colored minnows, Cayuga observations were made at this part of the station, and it minnows, Johnny darters and the Etheostoma iowæ. On was found to be little visited by fish in the daytime, but at the 26th of the same month another collection was made night, especially in April when the midges were taking in one of the shallow coves of the station, in water from 6 flight and the pupal form was abundant on the shoal, to 8 inches deep, with the following results: 100 straw- many perch and a single white fish were seen here. colored minnows, 80 Cayuga minnows, 75 blunt-nosed Blue-gills also used the bottom as a nesting or breeding minnows, 21 black-chinned minnows, and 1 golden place, building their nests in about three feet of water. shiner. The shoal was also inhabited by crayfish, which bred Late in May, besides the minnows mentioned above, the here, but mollusks and larger aquatic insects were rare, barred killifish, common sunfish, perch and Johnny if present at all. Some temperature readings were made darter were taken on this shoal, making, in all nine here, and are given below with accompanying data. species from this habitat. In the more gravelly places in this part of the station, crayfish made their homes under stones, as at station 23, and a Johnny darter's nest was found. It was reported also that white-fish visited this shoal in November to spawn.

The sedge marsh at this station doubtless had a large fauna, but it could be given little attention. The leopard The pond-weed zone of this station was from 100 to 150 frog was abundant on April 26, and large numbers of feet wide, and included that part of the bottom (from a frog's eggs and newly-hatched tadpoles were seen at little less than 5 feet to about 25 feet in depth) which is the same time in the shallow water of the marsh. Adult covered by a dense growth of pond-weeds and other midges swarmed here on this date, and the minnows aquatic plants. Here, as at other stations, the water at caught at the time had been feeding largely upon both the outer margin of the zone was found to have a depth the pupal and adult stages of these insects. of about 25 feet, below which the higher plants were apparently absent. The following species of fish were Station 3 has been classed with the shoal type, but it taken from this area in April by means of a large fyke differs from the stations discussed above in the fact that net: Large-mouthed black bass, common sucker, rock the shoal was much narrower, and had a bottom of marl bass, yellow perch, common sunfish and blue-gill. without sand or gravel. It included about 600 feet of the west shore of the lake, south of the outlet, except for a The plants of this zone are discussed on a subsequent small, shallow, rush-bordered bay, and the ditch running page (225). On them were found minute snails, from it into the marsh. The bay, on account of the amphipod crustaceans and midge larvæ. different environmental conditions, was treated as a Station 16 comprised the eastern shore with the distinct station, No. 7. The sedge zone of this station (3) adjacent shoal and pond-weed zone of a marshy was represented by a broad, wet marsh more than 500 peninsula, which is about 400 feet long and 200 feet feet wide at its broadest part, which was covered with a Annual Report for 1907 / Walnut Lake – Page 1 of 66 wide, and forms the east side of the bay from which runs water. In early spring fish were also scarce upon the the outlet (Pl. 27). The conditions here which can affect shoal, not visiting the shallow water at this time as they fish life in the lake are practically identical with those did in the eastern side of the peninsula. In late spring, described for station 3, but the shoal is slightly narrower. however, minnows and darters were common here, and The latter has a pure marl bottom, and a very scanty comparatively scarce along the other shore. The vegetation of dwarfed stonewort. Above the water's species were: blunt-nosed minnow, straw-colored edge a low, firm, dry, sedge-covered ridge, either ice or minnow, golden shiner, least darter, Johnny darter, and wave-formed, extended the length of the station, and at Etheostoma iowæ. In July many small perch and blue- the north end there was a short beach covered with gills were seen in the shallows, and larger fish of these bleached snail shells and their fragments, which, as and other species were also observed on the shoal. shown in Plate 26, were beautifully sorted into rows by During May it was a nesting place for sunfish. wave action. The pond-weed zone proper began in As this station was located near the head of a bay, at the about five feet of water, although there was a scant northern end the bottom sloped gradually from the edge growth of these plants in the shallower water towards the of the shoal to the 25-foot line, making the pond-weed shore. zone here unusually wide. At the southern end, on the The earliest observations at this station were made on other hand, the slope of the bottom was deep, and the April 6th, 7th and 8th, while there was still some ice in pond-weed zone was consequently very narrow, only the lake, and the marsh was frozen. At this time a few about 50 feet wide. Fish seemed usually abundant here, specimens of Etheostoma iowæ, blunt-nosed minnows especially in the wider part of the zone. However, this and a single Cayuga minnow were taken in a dip net, as may have been partly an apparent abundance, as it was they swarmed from hiding places beneath overhanging much easier to use the drag net in this habitat. The sedge-roots, along the edge of the marsh. At this time following species were taken: Large-mouthed black the water temperature was nearly at the freezing point, bass, yellow perch, common bullhead, yellow catfish, and no fish were seen moving about on the shoal, but in common sunfish, blue-gill, wall-eyed pike and rock bass. spite of this, crayfish, Mayfly and dragon-fly Iarvæ and Three species of turtles, the musk turtle, painted turtle caddice worms were found rather common in the and snapping turtle, were also taken in this zone. shallow water. Plate 27 shows the part of the shore along which these observations were made, as it SUMMARY. appeared in April. (a) The depth of water. The water upon the shoal varies Fish were never common on this shoal, even minnows from less than an inch to about 3 feet in depth. The being rather infrequent visitors. Perch were occasionally depth of water seems to have little effect on the seen at night, resting on the bottom as at other stations, distribution of the fish over the shoal, other than and in June the north end of the shoal was frequented restricting the larger fish, like the black bass, sunfish and by blue-gills, whose nests were numerous in about 3 feet perch, to the deeper parts. The minnows kept in shallow of water. A single nest each of the darter and a blunt- places near the shore. This was especially true in the nosed minnow were also found here. The pond-weed spring, when the minnows kept in the shallowest water in zone was well-marked, and while early in the season its which they could swim, possibly because of food and shoreward edge was limited by water about five feet temperature conditions. deep, later, in July and August, the shoal was encroached upon up to about the three-foot contour, by The shallow water also was chosen for nesting by a conspicuous growth of the characteristic plants of the several species. Some of these were confined to certain zone, and scattered plants of pond-weed appeared in depths, the blue-gills, for example, choosing water about still shallower places. The zone extended lakeward to 3 feet deep, apparently regardless of its relation to the where the water was about 25 feet deep, below which no shore or the pond-weed zone. plants could be found. In the late summer many more (b) Temperature. The effects of the water temperature fish were seen in this zone than at any other part of the on the movements of minnows is discussed in full station, the common species being perch, sunfish, black elsewhere (p. 202), but the statement may be made here bass, blue-gills and minnows. that the shallow water of the coves and lee sides of the Station 6 was the west shore of the peninsula described lake was usually found to be warmest, and that the above, with its adjacent shoal and pond-weed zone. It minnows sought such places, being apparently differed from the station just described in having no hard controlled in their movements by changes in water ridge along its shore, and in being located in a bay temperature. instead of on the open lake. The sedge marsh was wet (c) Bottom material. The minnows also apparently throughout the year, and the shoal was less extensive preferred stony-bottomed, barren shoals to those with than that on the eastern shore of the peninsula, while the marl bottom, probably because of the larger food supply pond-weed zone was broader. The station, as it in the former. appeared in early spring, is shown in Plate 28. (d) Plants. Almost the only plants on the shoals proper The marsh was apparently but rarely visited by fish, as were stunted stoneworts and scattered bulrushes. Their but a single specimen, a pike, was seen in its shallow Annual Report for 1907 / Walnut Lake – Page 1 of 66 relation to fish was not apparent except at breeding time, From the lakeward margin of the shoal the bottom when they afforded places of attachment for the eggs, sloped abruptly to a depth of 10 or 15 feet, then less and protection to the young. steeply to 25 feet. This area was occupied by a dense pond-weed zone, which began at the outer edge of the (e) Invertebrates. As noted elsewhere, these shoals bulrush growth and ended in about 25 feet of water. were the habitat of a greenish protozoan which was very abundant in spring. Crayfish were found here at all The fish fauna on the shoal could be, and was, studied seasons. Various insects were not abundant with the with care, because of the ease with which it could be exception of the midge larvæ and pupæ in April. Living approached from the lake without startling its mollusks were rare, but their empty shells were inhabitants. From early May to the middle of June the numerous. following species were seen or taken here: blue-spotted sunfish, common sunfish; blue-gill, large-mouthed black (f) Fish. Seventeen species of fish, as listed above, bass, perch, yellow catfish. In the early part of July were noted on the shoals of this type; the larger species schools of blunt-nosed minnows, golden shiners and were more common here at night than during the day. very small perch were commonly seen among the During the breeding season, the blue-gills kept other bulrushes on the shoal. During the latter part of July and species from the areas in which they had their nests. August this shoal, like most others, was almost deserted (g) Sedge zone. This area affects fish life more than any by fishes, except for occasional small blue-gills. The other shoreward zone, by furnishing a habitat for insects, marl bottom here was used by at least three species of which sometimes fall into the water and are eaten by sunfish as a nesting place, and probably also by the fish. In spring the flooded portions are sought by the black bass. grass pike for spawning grounds, and more rarely by While but little attention was given to the invertebrates of other species. Where these plants grow within the lake the area, some notes relating to the more conspicuous margin they furnish hiding places for numerous minnows types were made. Dragon-flies and damsel-flies were and other small fish. usually common, and underwent their final (h) The tree zone. Little was learned concerning its transformation on the marsh bulrushes. On May 25th a effect on the fish of the lake. small flight of May-flies was seen, but, in July, Dr. Needham found only a few dragon-fly and damsel-fly (i) The pond-weed zone. This was the general habitat of larvæ, and characterized the zone at that time of the most of the species visiting the shoals, and all except year as a desert so far as aquatic insects were five of the shoal fishes were also found among the pond- concerned. Whirligig beetles and spiders were often weeds. These exceptions were stonecat, chub-sucker, seen on the surface of the water, among the bulrushes. Cayuga minnows, barred killifish and miller's thumb. An interesting development of minute animals was noted The pond-weed zone may be said to determine to a on August 8th, when the surface of the water among the large extent the fish fauna of the shoals. bulrushes, and of the algæ and other plants, acquired a soot-like covering, which upon examination under the BULRUSH-COVERED SHOAL TYPE. microscope was found to be made up of innumerable one-celled animals related to Vorticella. As the chief difference between stations of this type and those of the barren shoal type was one of degree rather The following table gives the surface temperature than kind, the conditions were about identical, except for readings and related observations in the bulrush zone of the presence of many bulrushes in the bulrush-covered this station: shoal type. Two examples will be sufficient to show the characteristic conditions of stations of this type. Station 15 included the small cove on the west side of the lake, between station 11 on the north and 19 on the south, a distance of about 400 feet. The shore was marshy and covered with a dense growth of sedges which reached to the water's edge. The marsh was about 100 feet wide at the ends of the station, but much narrower at the head of the cove, where woods bordered The pond-weed zone does not become well defined the marsh. nearer the shore than about 50 feet, or until the water The shoal averaged about 20-30 feet in width, followed reaches a depth of 5 feet, for while the pond-weed plants the curve of the shore, and was broader at the south are present in some numbers among the bulrushes on end. The bottom was marl, and was covered by a dense the shoal, they do not form a dense growth except on growth of bulrushes (as shown in Plates 29 and 30) from the lake ward margin. The zone was broader than at the shore line to where the water reached a depth of some of the other stations described, extending from 3 to 4 feet. Growing with the bulrushes on the lakeward nearly 200 feet. A list of the plants of this shoal, were quantities of small stoneworts and habitat is given on a subsequent page (41). occasional pond-weeds, as in stations of the first type.

Annual Report for 1907 / Walnut Lake – Page 1 of 66 The fish fauna here was much like that of station 6. With and newly-hatched young. Plate 31 gives a general a water-glass perch could be seen in large numbers as view of station 4, including the beginning of the outlet. far below the surface as objects could be distinguished Plates 51 and 52 are snapshots of a long-eared sunfish (here about 12-15 feet). Schools of minnows appeared guarding its nest at this station. The other inhabitants above the submerged plants, and the Johnny darter and noted in the bulrush zone of this station were numerous Etheostoma iowæ were frequently noted in the shallower midge pupæ (seen on the bottom in April), Sialis adults parts of the zone. Both the gill net and fyke net were (common on April 23, as in other similar places at about used in this area, as well as hook and line, and the the same time), crayfish (numerous on the deeper part following species were found to frequent it in greater or of the shoal during the summer). The following less numbers: The perch (most commonly), yellow temperature readings were made at the water surface: catfish, bullhead, rock bass, common sun-fish, wall-eyed pike, common sucker, whitefish, large-mouthed black bass, blue-gill. For further details concerning these catches see page 53. Station 4 is the region included between the outlet on the west and the base of the peninsula forming stations 6 and 16 on the east. It is the shoal with its adjacent marsh and pond-weed zones. The marsh was a SUMMARY. continuation of that of station 6, but it was somewhat As pointed out above, the chief difference between this narrower than that of station 6, averaging a little more and the barren shoal type of station is the presence of than 100 feet in width. Shoreward it ended abruptly at the thick growth of bulrushes in shallow water, and since the margin of a cultivated field, and on the lake side this is the only peculiarity, the relation of the plants to extended to the water's edge. fish life is the only matter needing emphasis here. There were three sets of environmental conditions on From the fact that there were more large fish, chiefly this shoal, which differed so much as to deserve bass and sunfish, on the bulrush-covered shoals during recognition as substations. the breeding season in the spring than on those of the Substation a was an area of stony bottom, about 20 feet barren type, it was inferred that the conditions in the in diameter, at the west end of the shoal, probably former habitat were more attractive to the fish than those formed by a load of field-stone dumped in here from the of the latter. Four reasons for this seem to be apparent, cultivated land near by, and possibly spread out to some viz.: (1) The bulrushes afford hiding places for the nests extent by ice-action. PI. 31 shows this substation in and young, as well as for the old fish during the breeding summer, after the bulrushes had grown, making season; (2) the roots and underground stems of the conditions similar to those at substation c. Small fish plants serve as good places for the attachment of the were seen here whenever the substation was visited, eggs; (3) the water is less liable to be affected by strong either day or night, throughout the season, and were waves where the plants are dense; and (4) these shoals often abundant over the stones in this habitat when none are apparently better feeding grounds than the barren could be found on the rest of the shoal. ones, as collections made from them indicate that the larvæ of dragon-flies, May-flies and midges, as well as Substation b was the barren middle part of the shoal. It crayfish, seemed more numerous among the plants than had a pure marl bottom which was without visible plant on the open shoals, except those with stony bottoms. covering, and fish were seldom seen here. Substation c was the east end of the shoal. It had a SWAMP LOOSESTRIFE-FRINGED TYPE. considerable growth of bulrushes which made it like station 15. The bulrush zone was narrow here, and The swamp loosestrife, which characterized stations of covered with water about a foot in depth; the bottom was this type, is described at length on a subsequent page marl covered with low stoneworts growing between the (44), and also in another publication of this Survey.* In bulrushes; and it sloped abruptly to deeper water from Walnut Lake it is limited to the two areas described the edge of the shoal. In April the following fish were below, which form a very distinct type of stations. taken in a net from this place: pike, perch, common and Station 31 included a part of the west shore of the south long-eared sunfish. In May and June, sunfish, black bay of the lake and was about 300 feet long, and from bass, perch, blunt-nosed and straw-colored minnows, 10 to 30 feet wide. It was bordered along the water's the least darter and Etheostoma iowæ were common in edge by a thick growth of the swamp loosestrife, which this zone, and in July it was used extensively as a grew in water from a few inches to slightly more than 2 breeding place by the common, the blue-spotted, and feet in depth. Plate 32 shows this station in April, and the long-eared sunfish, which made their nests in water Plate 33 in the latter part of June. about 15 inches deep. Notes on their nesting habits are given on subsequent pages (32, 33). The station had four distinct zones of vegetation. These were (named in order from the dry ground to the deep The minnows and small individuals of other species water): (1) sedge zone, (2) swamp loosestrife zone, (3) were abundant about these nests, feeding on the eggs Annual Report for 1907 / Walnut Lake – Page 1 of 66 water lily zone, (4) pond-weed zone. The most about eighteen inches deep. No data on the interrelation conspicuous plant in each of these zones was the one between these conditions and the fish were found. which gave to the zone its name. The zone of aquatic plants extended outward for about The sedge zone was a tract of marsh several acres in 100 feet from the lakeward margin of the loosestrife extent, and covered by several inches of water which zone to a depth of from 8 to 10 feet. It may even have surrounded the stools of the tussock sedge, the common extended farther, since the bottom below that depth was sedge here. not studied carefully. The conspicuous plants of this area differed at different times during the season; first, The swamp loosestrife zone, as it appeared from the water lilies appeared in early summer, forming an lake, is shown in Plate 34. Fish were seldom observed incomplete zone, then, the white water crowfoot covered in the shallow water among the stools of the swamp the water with its dainty blossoms (Plates 39 and 40), loosestrife, and none were caught with a dip net, but on and later, the outer parts of the zone were occupied by May 30, a trammel net placed along the fringe captured several kinds of pond-weeds. The bottom in this habitat three species of sunfish, the blue-green, common, and a was a black mud, incipient peat, formed from decaying specimen of Lepomis euryorus. aquatic vegetation, and the leaves and other parts of *Davis C. A. The Formation and Distribution of Peat Bogs in the marsh and land plants which had blown into the lake. Northern Peninsula of Michigan. Report Mich. Geol. Surv., 1906. Immediately lakeward of the swamp loosestrife zone, in The relationship of the pond-lily zone to the last is clearly water about two feet deep, was an irregular strip where indicated in Pls. 33 and 34. The water in which the the black mud was covered by undecayed water-logged water-lilies grew was from two to six feet deep, and the twigs, leaves and other plant debris. This strip was bare bottom was covered by a thick growth of stoneworts and of plants, except for a few stoneworts and floating some pond-weed. According to our observations, fish filamentous algæ. The undecomposed material was were never abundant here; on June 24th some young probably much increased by a mass some 50 feet long blue-gills and black bass were noted. and 12 wide, of stems of white water crowfoot, which in August was swept over it by wind, and became lodged The pond-weed zone extended from the lakeward against the swamp loosestrife (Plate 39). margin of the pond-lily zone into deep water, and unlike the other zones of the station, had a large fish population Large schools of blunt-nosed minnows were often seen during the summer. The principal forms were young In the parts of this zone where the vegetation was perch and minnows. Blunt-nosed and straw-colored dense, and other small fish, especially golden shiners minnows, common and golden shiners were always were usually found. The least darter was abundant in noted to be abundant in the shallower parts of the zone, May and June, and probably bred here. The common whenever it was visited, and were peculiarly active, sunfish used the shallow, bare area near the inner darting about as if at play, while in apparently peaceable margin of the zone as a nesting place, and the shallow association with them were seen black bass, rock bass water of the entire station seemed a favorite resort for and perch. perch fry, in early June, and for young minnows (too small for determination) which were very abundant. Station 26, the other example of the type of station Some small chub-suckers were also taken here on June under discussion, included the north shore of the bay of 15. The musk and painted turtles were common at this the lake, and was the extreme northern station. It station. differed from 31 in being sheltered on three sides by wooded hills, in being only 35 feet deep at its deepest MARSH BAY TYPE. part, and but 8 or 10 feet deep for about 100 feet from the shore. There were three well-defined zones of Of the two stations of this type station 7 was most often vegetation, the sedge, swamp loosestrife, and that of visited, because it was very accessible, and because of wholly aquatic plants, including water-lilies. Plates 35 to the ease with which the large number of species of fish 40 inclusive, show various aspects of this station. inhabiting it could be studied. For these reasons this station was given more attention than any other on the The sedge zone lay across the mouth of a small valley, lake. It included the small bay, or cove, in the marsh on in which, during the wet part of the year, runs the the west side of the lake, which was mentioned in intermittent stream which drains the wood-covered describing station 3, and an area of yellow water-lily slopes north of the lake. The vegetation of this area is plants at its mouth, which was considered a part of the well shown in Plate 35. It lay between the swamp station, because it was the refuge of many of the fish loosestrife zone near the margin and the shrubs that frequenting the bay. A ditch 5 or 6 feet wide, cutting bordered the woods. Near the level of the water the across the marsh from west to east, enters the bay. The plants were chiefly tall-growing species of sedges, with a latter was circular in form, and bordered by bulrushes small area of cattails near the east end. and a sedge marsh. At the water's edge on the north The swamp loosestrife zone followed the curved shore side of the bay a group of swamp loosestrife plants were of the north end of the bay for about 100 feet, and was established, and another group was situated on an old from 10 to 20 feet in width. The plant grew from the muskrat house in the middle of the bay. The bulrush place where the soil was simply moist out into the water growth forms projecting points on either side of the bay, Annual Report for 1907 / Walnut Lake – Page 1 of 66 which nearly close its mouth, and partly cut it off from the subsequent page (54) the full data regarding the food of lake. Plates 41 and 42 show the type of shore these specimens may be obtained; it may be said here vegetation and other features of this station. that they had been feeding largely on crayfish and the larvæ of aquatic insects. In the spring the average depth of water in the bay was about a foot, in the summer it was less than this over After the middle of June large fish almost entirely most of the bottom, because of the lower water level of disappeared from the bay, as they did from other shallow the lake, and the dense growth of submerged plants parts of the lake, but small fish were common here all which carpeted a large part of the area. The bottom was the summer. During May, large schools of minnows, of covered by a layer of black, soft, peaty ooze, above a which the blunt-nosed was the most common, were seen different substratum, apparently marl. Many types of at nearly every visit to the station. With this species plants were found here, and a description of the relations were associated at this time the straw-colored, Cayuga, of those noted during the spring will be found on a and black-chinned minnows, golden shiner and barred subsequent page (222). It is sufficient to say that the killifish. In August golden shiners and black-chinned dense growth of vegetation at this station was never so minnows were the common species, while those first luxuriant that it interfered to any marked extent with the mentioned became scarce. Least darters were fish life by restricting swimming space over any numerous until about the middle of June, after which considerable area, for there were always a few inches of none were seen, while young perch, about an inch long, water over the tops of the submerged plants, besides appeared in large numbers and were noted until the many bare spots covered by accumulations of water- middle of July, after which few were seen. A list of logged chips, sticks, bits of bulrushes and other coarse important fish taken at this station will be found in the fragments of vegetable matter, brought here by waves table on page (54). In addition to those given above, this and surface currents. Such a spot in the south part of list includes horned dace or chub, common sucker, the bay, having an area of three or four square yards, yellow catfish, bullhead, tadpole stone cat, pike, rock was covered by but a few inches of water, yet minnows bass, blue-spotted sunfish, wall-eyed pike, and were more abundant upon it than in any other part of the Etheostoma iowæ. station. The invertebrates of the station were not carefully Easterly winds drove waves of considerable height into studied, but the more conspicuous forms seen at each the bay, in spite of the protecting bulrush points, and the visit were noted and usually preserved when collected. water was sometimes turbid from this cause. This Of these may be mentioned the red-bellied leech, undoubtedly affected the life relations of the bay, by crayfish, amphipods, dragon and damsel-flies in all preventing its being clogged with aquatic vegetation. stages of development from eggs to adults, caddice- flies, water striders, whirligig beetles Zaitha sp., back One type of plants found in the bay, the bladderworts, swimmers, and other insects. Further information may have a slightly unfavorable effect upon the fish life, relating to the insects of this station will be found in the by lessening the food supply of some of the smaller report of Dr. Needham, in Appendix III, page (56). species. These plants are said to be carnivorous,* the bladder-like expansions on their leaves and stems The conspicuous vertebrates (other than fish) of this serving as traps and absorptive organs for small station were the large green frog, and turtles of three crustaceans and other animals which may enter them. species, the musk, painted and Blanding. The musk On July 5th some material from one of these "bladders" turtles laid their eggs in the remains of a muskrat house was examined, and was found to contain several minute near the south side of the bay. The red-winged crustaceans of the kind used as food by small fish at this blackbird and marsh wren were common in the sedge station. This effect must be very insignificant, however, zone, and probably bred there during the early part of as the plants are few, and the bladder-like traps are only the summer, and in late summer the least bittern was operative on such organisms as enter them. noted several times. A muskrat house, apparently not inhabited, was located near the center of this bay, in a *Darwin, C. Insectivorous Plants. patch of loosestrife, see Plate 41. This station was visited almost daily from about the first Station 41 was the second one of this type. It of May until August 15th, and, since, owing to the comprised the small enclosed cove and the adjacent concealment afforded by the bulrush points, it was easy shoal located at the southeast bend of the south bay. to approach the bay from either side without disturbing The general appearance of the station is shown in Plates the fish, many very satisfactory observations were made 43 to 46 inclusive. It resembled station 7 in being a upon their habits. Until about the middle of June full- small, partly enclosed body of shallow water, into which grown specimens of black bass and sun-fish were found opened a stagnant ditch cut through a marsh which present at almost every visit, and, as but few sunfish forms its landward margin, and in having very abundant nested here, it is probable these species come here for vegetation growing on a bottom composed of very soft, food. A trammel net set across the bay at this season black, peaty mud. It differed from the other station in caught individuals of the following species: black bass, that it was not exposed to the force of strong lake waves, blue-gill, common sunfish, blue-spotted sunfish, rock and in being separated from the deep water of the main bass and common bullhead. From the table given on a lake by a broad shoal. The highest part of this shoal Annual Report for 1907 / Walnut Lake – Page 1 of 66 was a wave-formed spit which was above the water SUMMARY. level, and projected southward to form the western side of the cove (See Plate 43.) The waves were constantly The two stations included in this type are alike in being driving sand and other materials down the shore of the small, shallow coves, with bottoms composed of soft, bay, and depositing them in the quiet water at the end of black mud, on which plants grow in great profusion. the spit, thus elongating it. Other conditions that Each station was located in the midst of a marsh, distinguished this habitat from station 7 were the greater through which a ditch had been cut, but in which water is depth of the black mud at the bottom (more than three stagnant. Station 7 was located so that it frequently feet), and the greater luxuriance of the vegetation in received the full force of the waves caused by easterly parts of the bay, especially the northern part, where from winds sweeping across the lake open, but station 41 was early summer the water was completely clogged with free from this factor, as it was situated near the plants of a number of species (see the following pages) shoreward end of a protected bay, and all waves that which formed a dense mat over the surface (see Plate entered it were small. Station 7 also opened into deep 45). water, being separated from it only by a narrow shoal, while station 41 was bordered by a broad marl shoal. The shoal adjacent to the mouth of the bay supported a The greater depth and richness of mud at the bottom, growth of bulrushes (Plate 46) on the marl bottom, out to and less exposure to active wave action, in station 41 where the water was more than three feet deep. The permitted a denser and more thrifty growth of plants, and sand spit supported a rather sparse growth of sedge with this, compared with station 7, limited the amount of some swamp loosestrife, as shown in Plates 45 and 46. space available for fish movements. On the whole, fish In April and May small fish were very numerous in, the were present in greater numbers and more constantly in shallow water of the cove, but they became fewer as the these two coves than in any other areas of similar size in plants grew up from the bottom and decreased the depth the lake. Fish of many species and in large numbers and area of the open water. At low water level in August used these stations as feeding grounds, especially the the water, except for spots of floating algæ, was only young of such important types as black bass, perch, about six inches deep over the plants in the south part of blue-gill and bullhead. A few nests of breeding fish were the cove, while in the northern part the top of the water found at station 7, but none at station 41. plants formed a dense mat on the surface of the water, and there were no open areas. BULRUSH SHOAL TYPE. A number of collections of fish were made through the On the east side of the lake, 150 or more feet from season at this station, the details of which may be found shore, was a small island at low water. This island was on a subsequent page (250). The species taken or seen about 200 feet long and 100 wide, but it was nearly here were, pike, blunt-nosed, straw-colored, black- submerged during high water, except for a small area on chinned and Cayuga minnows, golden shiner, the south side, which is permanently above ordinary high Etheostoma iowæ, Notropis anogenus, tadpole stone water. The water between this island and the mainland cat, barred killifish, rock bass, blue-spotted sunfish blue- averaged from two to three feet in depth, and only gill, common sunfish, large-mouthed black bass, perch, exceeded five feet along its shoalless margins. This Johnny darter, least darter, yellow catfish, common shoal area was station 54; it had, usually a marly bottom, bullhead. and was covered with a more or less dense growth of As noted above, the April and May hauls of the nets bulrushes, thickest in the south half and thinner on the secured many more species and specimens than those east end and west sides, where the stations merged into of the succeeding months. An interesting observation on stations 46 and 49. On parts of the shoal where biological relations was made here in August, when it submerged plants grew, the marl was covered by a layer was found that the small fish were again abundant in the of black organic material. paths which had been opened across the masses of This seemed to be the most important shallow water water plants in the end of the bay by muskrats or turtles. area of the lake, as far as the fish life was concerned. It (The musk turtles used an old muskrat house on the is shown upon the map, Pl. 15, between the dotted lines south shore of the station as a place for the incubation of on the peninsula marked with the station number and the their eggs, and on June 25th ninety eggs, in groups, as shore line. The data for the map was taken while thick shown in Plate 67, were uncovered here and ice covered the area, and, with the island, this station photographed.) was mistaken for a marshy peninsula. Plates 47 to 50, inclusive, show some of the characters of this station. The only notes on invertebrates made at this station were that on April 10th, large red midge Iarvæ were very Stoneworts were abundantly distributed over the bottom, abundant on the marl bottom of that portion of the lake generally growing with the bulrushes, but one circular included in this station, and a week later the adult area of about 60 feet in diameter near the eastern border insects were numerous in the air, and pupa skins of the station was so densely covered by these plants covered the water. that the bulrushes could not grow there. The stoneworts grew at least two feet high here in August, reaching almost to the surface; the open water here presented

Annual Report for 1907 / Walnut Lake – Page 1 of 66 conditions so different from those where the the The plant associations divided this station into four quite bulrushes grew that it was called substation 54a. A part well-marked zones, the swamp, the sedge, the cattail of the margin of the clear area is shown in Plate 49. and the bulrush and waterlily zones, each presenting some peculiarities as a habitat for fish. Among the bulrushes cattails and other aquatic plants were numerous, sometimes, as in the case of the water- The swamp zone (Plates 51-55, inclusive) was situated lilies, covering the water surface (Plates 48 and 49). on the lake ward border of a large marsh, and had a The species of plants found here are given on a heavy growth of trees and shrubs. These plants grew in following page (40). very wet soil, with pools of stagnant water, a foot or two Fish were common here until the latter part of the deep, between the trees and clumps of bushes. These summer, when, as in other shallow water areas, they pools during the summer were covered by an almost became scarce. Large numbers of black bass used it as unbroken carpet of duckweed (see Plate 55). Sedges a nesting place in May, making their nests and laying and many other herbaceous plants grew among the their eggs in from 12 to 15 inches of water, but there trees and shrubs, forming a dense border in the part of were few young reared here. The adults were speared the zone towards the lake. from their nests by fishermen. Sunfish, on the other Numerous tadpoles and three species of fish (mud hand, while common, did not breed here, so far as could minnows, young perch and brook sticklebacks) were be determined. Other species of fish noted at the station caught in a dip net in these pools on June 16th. This were pike, blunt-nosed and black-chinned minnows, was the only place where the sticklebacks were found golden shiner, chub sucker, bullhead, yellow catfish, about Walnut Lake. Plate 55 shows part of the interior of blue-gill and rock bass, Lepomis eurzorus, long-eared the swamp zone. sunfish, yellow perch, Johnny darter, probably Etheostoma iowæ. The sedge zone was distinct only in the eastern part of the station, where it consisted of a narrow belt of sedges The trammel net was found most effective for catching close to the shrubs of the swamp zone. The ground fish at this station, and during May a number of hauls here was wet throughout the season, but there was not were made with it. The collections and notes made are enough water to allow fish to move in it to any extent. given on a subsequent page (54). Plate 72 shows this net set across station 54a. The cattail and bulrush zone began at the shoreward edge of shallow water, as shown in the figures, and was. Next to fishes the birds were the most conspicuous really a double zone, the cattails in very shallow water, vertebrates of this station, two species, the red-winged and the bulrushes extending out to depths of five feet, in blackbird and marsh wren, being common. The places more than 200 feet from shore. Plants other than blackbirds were particularly numerous, and bred among those mentioned were present in different parts of the the bulrushes. When this station was visited on the night zone, sometimes in abundance, as at the west end of of June 12th, hundreds of these birds were found the station, where quantities of a species of horsetail roosting on the stems of the plants. In July, large grew in the shallow water with the bulrushes. About the numbers of barn swallows used the bulrushes as resting middle of the station was a small cove, where the places at night. Two species of turtles, the musk and the bulrush growth was sparse and the cattail grew in small painted, were often seen; on August 1st one of the first clumps; in summer the water in this cove was covered named species was observed eating a dead black bass. with duckweed (Plate 53). There were several muskrat houses at this station, The waterlily zone was present along the west portion although none of these animals were seen. Insects of of the station, and became noticeable about the last of several kinds were abundant, the dragon-flies and May, at which time the floating leaves of the lilies damsel-flies being the most noticeable, as-they were appeared. At the west end of the station these plants very active when weather conditions were favorable. extended out from shore for some 200 feet to the edge Late in April midge larvæ were found in collections made of the broad shoal. from the marl bottom of the station, and on May 21st adult midges of a different species from that so abundant The shallow water of this station was frequented by over the marshes in April were noted on the bulrushes. many species of fish, and numerous individuals were seen at every visit made when conditions were favorable for observation. This station was not visited regularly, SWAMPY SHORE TYPE. however, and, because of the rank vegetation over much Station 40 was the only example of this kind. It was of its area, but little collecting could be done. According located at the northeastern part of the lake, extending to observations, the large fish, like black bass and about 300 feet in a westerly direction from the point (see sunfish, were common on this shoal, as upon the others map) where the shore bends almost at right angles, after studied, only during the spring and early summer, turning northward. It included the north end of the wide although sunfish nested here in shallow water. Minnows northeast bay, and differed from other stations in that it abounded both in the spring and summer, but were most supported a tree-covered swamp, and an unusual numerous in May, when the following species were amount of aquatic vegetation. seen: blunt-nosed, straw-colored, black-chinned and

Annual Report for 1907 / Walnut Lake – Page 1 of 66 Cayuga minnows and golden shiner. On May 21 the chiefly diatoms, constituted almost the only plant life of Cayuga minnow appeared to be spawning on the shoal. deep water, the higher plants, when found at all, being of Other fish seen or taken here were the mud minnow scant growth or restricted to small patches in the (very common in the dense growth of plants near the shallower places. shore) chub-sucker, yellow catfish, common bulhead, The bottom in deeper water appeared to have three barred killifish, rock bass, perch, Etheostoma iowæ, and distinct zones of quite different types of soil, according to least darter. The young of several species of fish were the depth. Marl was the chief bottom soil over the very numerous here in early summer, among others, shallow parts of the lake, and it extended only to a depth those of the perch and sunfish. of about 39 feet. At depths of 40 to 50 feet, a loose Of the invertebrates casually noted at this station the textured brown mud covered the bottom, and was dragon-flies and damsel-flies were common, and replaced at a slightly greater depth than this by a thick numbers of their empty larval cases were attached to the layer of fine-grained blackish mud which covered the bulrushes. A leaf-eating beetle, Donacia, was common bottom of the deepest part of the lake. about lily pads. The whirligig beetles were common in the summer. Sialis adults appeared in large numbers Station 200, the first deep-water station to be among the bulrushes late in May, and one was observed considered, was in that part of the bay at the west end of laying eggs on the stem of one of these plants on May the lake, west of the marshy peninsula and of a line 29; at this time and later, black, waxy, oblong masses of running straight south from it. It had an area where the eggs of these insects were often seen on the bulrushes. water was from 30 to nearly 60 feet deep. The method used to discover the nature of the bottom at this station The shoal here was one of the few places where living was to draw a hook-and-net drag across it in several snails were common, although empty shells were directions. In May, while dredging with this along the abundant on most shoals and on the shores of the lake. eastern border of the station, a mass of water-moss On May 16, numbers of small specimens of these caught on the hooks and was brought up to the surface, mollusks were seen on filamentous algæ, and proved to but, as it was not found again in several trials, it seems represent four species, Planorbis parvus, Amnicola probable that it was drift material, or occurred over but a limosa, Valvata tricarinata, and a species of Pisidium. In small area of the bottom. On July 20 three hauls more April two species of leeches were collected at this made over the east and central parts of this station, in station. Of vertebrates, large green frogs were usually water from 40 to 50 feet deep, but none of the larger seen or heard throughout the summer. Birds were plants were found, except a small fragment of hornwort, common in the swamp, but were not studied. The red- which is a generally rootless form, hence without wings were abundant, and lived and nested among the significance. cattails, as did also the marsh wrens. Kingfishers were common at this station. In each case the net part of the drag was brought up filled with grayish-brown mud, the temperature of which, taken as soon as possible after reaching the surface, DEEP WATER TYPE. was 15° C. A few midge and Corethra larvæ were found As already stated, the types of stations thus far in this mud. discussed generally include portions of the shore, and As it was impossible, on account of the depth of the extend only to the lake ward boundary or deepest part of water, to make observations on the fish life at this the pond-weed zone, which does not extend deeper than station, except rarely when fish were seen near the about 25 feet deep. Around much of the shore this surface, practically all the information gained concerning depth is reached about 200 feet out, as shown by the 25 the fish life was through collections. One of the few foot contour line on the map, Plate 14. In one region direct observations was made on July 19, when a large (station 46, at the eastern end of the lake), however, this school of perch-fry was seen near the surface, about line is some 700 feet from shore, while at the north end 300 feet from shore, where the water was about 40 feet of station 24 (near the extreme north end of the lake) it is deep. These fish averaged about an inch and a half only about 50 feet from the shore. As indicated above, long. The following species of fish were taken by the the average width of the belt of water shallower than 25 fyke and gill nets at this station during the season: feet is probably between 200 and 300 feet, so that by far perch, common, sucker, white fish, and wall-eyed pike. the larger part of the bottom is more than 25 feet from The suckers and white fish netted here had been feeding the surface. All stations within this area are called deep- on midge larvæ and on the crustacean, Daphnia. A water stations. tabulated statement regarding the collections will be Observations seemed to show that the conditions in the found on a subsequent page (54). entire deep-water area were similar, the chief differences Station 225 was that area on the southwestern part of being the depth of water, and as this undoubtedly affects the lake, where the water was from 60 to 80 feet deep. fish life directly or indirectly, differences in depth were It began just east of station 200 and completely made the basis for classifying stations. The surrounded station 250, which included that part of the observations and collections made in this deeper part of bottom over 90 feet from the surface. The bottom the lake all point to the fact that microscopic algæ, material at station 225 was a fine-grained; compact

Annual Report for 1907 / Walnut Lake – Page 1 of 66 deposit of black muck which was light in weight, and shown by the contour map (Plate 14), it was located on supported a considerable microscopic fauna and flora. the southwest side of the lake, from 500 to 1000 feet The former included, during late summer, numerous north of station 23. It was elliptical in shape, and about midge larvæ and the latter, diatoms. (See descriptions 200 feet wide and 700 feet long. of the bottom samples taken at station 200 above, which were more carefully studied than those from this station.) In July, while making collections of midge larvæ at this It is evident from the study of many and other deep-water stations, an apparent relation was observed between the numbers of Iarvæ taken and the samples that the soil of the bottom at this depth of water in which the collecting was done, in that station was the same constitution over its the larvæ seemingly increased in numbers as the water entire area. It is dark gray, almost black became deeper, but much more work needs to be done to confirm this observation. However, it should be in color, and is made up of very fine pointed out that if the deep water has more of these particles, so small and light that it takes organisms than the shallow, there would be more food more than an hour for them to settle to the for fish in the deeper parts of the lake, and certain species would probably tend to congregate there. In bottom of a shallow dish. A microscopic April a few temperature readings were made at this examination showed black and light- station, by the use of a thermo-phone, which later got brown inorganic particles, and the out of order and could not be used. The results are given below: remains of organisms such as shells of diatoms and Entomostraca. Living diatoms, rotifers and other microscopic forms of plant and animal life were abundant, and midge larvæ, in cases made of soil particles, were present in great Fish taken, here (by the use of the gill-net) were the numbers, especially in late summer. whitefish and common sucker. Details of the food and Sayomyia larvæ were also common. (See other data relating to these fish will be found on pages 53-54. the report on insects, Station 250 included the deepest part of the lake, where the water ranges from 90 to 101 feet deep. As APPENDIX III. NOTES ON THE AQUATIC INSECTS OF WALNUT LAKE WITH ESPECIAL REFERENCE TO A FEW SPECIES OF CONSIDERABLE IMPORTANCE AS FISH FOOD. by JAMES G. NEEDHAM. of this report). The only fish caught at this station were whitefish which were taken by means of the gill net, and but few specimens of these were secured. The identifiable material in the alimentary canal consisted chiefly of midge larvæ.

The following table gives such temperature readings as were made here; the surface readings were made with a On August 25 and 26 Dr. John Eastwood, with the standardized thermometer, and those from deep water assistance of Professor Jacob Reighard, determined the with the thermophone, except those made on August 25, gas contents of the water at this station at different in which maximum and minimum thermometers were depths where the bottom was a hundred feet below the used. surface. The purpose and results of this work are given in the following report written by Professor Reighard: "At a depth of nearly 30 meters, there are found living in the bottom ooze of Walnut Lake numerous larvæ of a species of midge or Chironomus, and in the water immediately overlying the bottom, is an abundance of Daphnia. Whitefish were found to feed on both of these forms. Since in most lakes of this depth and area the Annual Report for 1907 / Walnut Lake – Page 1 of 66 oxygen is practically exhausted in the deeper waters fifteen meters or less there is two or more times that during the summer, so that Chironomus, Daphnia and amount. fish cannot live there, an effort was made to learn what *The values given for oxygen were those obtained in the last of three the conditions at the bottom of Walnut Lake were which series of observations except the starred values, which are the made it possible for these animals to thrive there in mid- averages of all observations made. summer. All values obtained for Co2 are given in the table. "The methods used were those described by Whipple †Birge, E. A., 1907. Gases Dissolved in the Waters of Wisconsin and Parker* and the results are given in the following Lakes. Transactions of the American Fisheries Society, 1906, pp. 143- table. 163, 12 figures.

*Whipple, George C., and Parker, Horatio N., 1901. On the amount of "If we compare this condition with that found by Birge in Oxygen and Carbonic Acid Dissolved in Natural Waters and the Effect Wisconsin lakes, it appears that in Lake Mendota the of these Gases on the Occurrence of Microscopic Organisms. oxygen is entirely exhausted at the end of August at a Transactions of the American Microscopical Society, Vol. XXII, pp. 103-144, pls. XIX-XXII. depth of about thirteen meters. This exhaustion is attributed by Birge to the decay of the abundant organic Table showing the amount of dissolved oxygen and matter present in the form of plankton in the surface carbon dioxide at various depths in Walnut Lake, waters of the lake. As this plankton falls to the bottom in Oakland Co., Michigan, on August 26, 1906. mid-summer and decays the oxygen is exhausted, since in the process of oxidation it enters into combination with the organic matter. The bottom Waters of this lake are thus devoid of oxygen during the greater part of summer, and at the end of that season no fish or other higher animals can live in them. At other seasons these deeper waters contain oxygen. Lake Mendota is thus in sharp contrast to Walnut Lake whose waters contain oxygen at all depths even in mid-summer. Not only are the deeper waters of Lake Mendota unfit to support fish in summer by reason of their lack of oxygen, but they are unfit on account of the absence from them of sufficient animal life to serve as food for fish ‘to support any considerable

amount of fish life at any time of the year’ (Birge). "The results are also shown in graphic form in the diagram, Fig. 18. From these results it appears that the volume of oxygen present at the surface is that usual in lakes at this time of the year, as shown in Birge's (1907) chart† of Lake Mendota on August 31. "To a depth of about five meters the oxygen diminishes somewhat and then increases until at six meters it is slightly greater than at the surface. In this respect the lake resembles Elkhart lake and Beasley lake, as described by Birge, except that the increase is much less than in those lakes. As pointed out by Birge this increase in oxygen is due in Beasley and Elkhart lakes to the presence at a distance of five or six meters below the surface, of algæ, which in their ordinary metabolic processes use up carbon dioxide and liberate oxygen. In this way the water at this depth comes to have in solution an amount of oxygen in excess of that in the more superficial layers, and the total volume of water capable of supporting animal life is thus materially increased. Below seven meters in Walnut Lake the volume of oxygen per liter of water rapidly diminishes. At a depth of twenty-eight meters it is still about one Figure 18. Diagram showing results of gas analyses of water centimeter per liter, and at twenty-nine meters it is six or at different depths at Station 250. seven-tenths of a centimeter per liter. As a glance at the map shows (Pl. 14), a depth of twenty-nine meters "In contrast to Lake Mendota is Trout Lake, Wisconsin, occurs over a very small part of the lake bottom, so that also investigated by Birge. At the bottom this lake we may safely say that over nearly the whole bottom in contains about the same amount of oxygen as Walnut mid-summer there is present not less than one cubic Lake, but between the bottom and the eight meter level it centimeter of oxygen per liter of water, while at depths of contains a good deal more. Above the eight meter level it contains about the same amount of oxygen as Walnut Annual Report for 1907 / Walnut Lake – Page 1 of 66 Lake. The lake was examined on September seventh. appear to have lived, and there is little reason why the Birge reports that the true white fish and the lake trout species should not be present in the lake now. inhabit its deeper waters during the summer. It thus The fish fauna of Walnut Lake was found to be very appears that these fish are able to live where the oxygen different from that of the few others in its neighborhood content of the water is not more than one cubic which were examined. Two of these, Simpson Lake and centimeter to the liter. This amount of oxygen is present Orchard Lake, will serve as examples. The first named in the bottom water of practically the whole of Walnut is a small body of water less than a half-mile west of Lake during the summer. It is its presence there which Walnut Lake, whose outlet joins that of the latter, thus enables the lake to support whitefish. Not only does the forming a water-way between them. This lake abounds water at the bottom contain sufficient oxygen to support in calico bass, Pomoxis sparoides, but none were found the whitefish, but what is quite as important it contains in Walnut lake. In Orchard Lake 21 species of fish were sufficient oxygen to support the food upon which the taken at the single visit made on June 18, six of which whitefish largely lives, the Chironomus larvæ and the were not collected at Walnut Lake. These six species Daphnia. are as follows: "No investigation has been made of the amount of 1. Bow fin, Amia calva Linnæus. One found dead near organic matter or of plankton in the waters of Walnut shore. Lake. It is to be presumed that Walnut lake, like Trout Lake, contains relatively little plankton. Of lakes 2. Lake herring, Argyrosomus artedi, (Le Sueur). One otherwise alike that one which contains the greatest found floating dead. amount of plankton will contain the least oxygen in midsummer, while that one which contains the least 3. Rosy-faced minnow, Notropis rubrifrons (Cope). Abundant. plankton will contain the greatest amount of oxygen in midsummer. Lake Mendota belongs to the first of these 4. Brook silversides, Labidesthes sicculus (Cope). classes, while Trout Lake, and presumably also Walnut Abundant. Lake, belongs to the second class. In lakes of the first class the oxygen of the deeper waters becomes 5. Schilbeodes miurus (Jordan). One taken. exhausted in summer by the decay of the abundant 6. Manitou darter, Percina caprodes zebra (Agassiz). plankton and these waters are therefore unable to One taken. support animal life. In lakes of the second class the oxygen does not become exhausted by the decay of the The remaining fifteen species taken on this day and also plankton and the deeper waters are able to support fish found in Walnut Lake are as follows: and fish food throughout the year". Blunt-nosed minnow, Cayuga minnow, straw-colored minnow, common shiner, Notropis anogenus, barred killifish, blue-green sunfish, long-eared sunfish, blue-gill, FISH OF WALNUT LAKE. common sunfish, black bass, perch, Etheostoma iowæ, BY T. L. HANKINSON. Johnny darter and least darter. These observations show the value of detailed examinations of different As the work of the party was concentrated on problems lakes from the standpoint of fish environments, for the concerning the fish-life of the lake, efforts were made to differences in fish faunas are possibly due to differences obtain specimens of all of the species in the lake. Thirty- in the environmental conditions. one species were taken, and, although other species are probably to be found, this collection may be taken as highly representative of the fish fauna of the lake. CONDITION OF FISH. Among the species that we may have overlooked is the In a general way it may be said that fish thrive in Walnut lake trout, several plantings of which have been made in Lake. The mortality of individual fish, due to natural the lake at various times, both by the Michigan Fish causes, was apparently small, and relatively few dead Commission and the United States Fish Commission. fish were found, although in early spring, dead sun-fish, The following table will show the number and date of chiefly blue-gills and blue-spotted sunfish (the latter each planting. more often), were occasionally found floating or cast ashore. In summer, perch were commonly found dead, while on the other hand, not more than six dead white- fish were seen during the entire season. All of the fish caught appeared in a normal or healthy condition, and some, notably the black bass, were conspicuously fat. Those planted by the U. S. Commission were yearlings. In 1890 the Michigan Fish Commission examined SPECIES, RELATIVE NUMBERS AND Walnut Lake, and, with a gill net set in from 70 to 80 feet of water, caught 6 lake trout, the largest of which ECONOMIC IMPORTANCE OF THE FISH. weighed one and one-half pounds. The planted fish thus Of the total number of thirty-one species of fish collected in this lake, two-thirds, including practically all of the food Annual Report for 1907 / Walnut Lake – Page 1 of 66 fish in the list, may be considered common. These are ANNOTATED LIST OF FISH IN WALNUT given in the list below, as nearly as possible in the order LAKE. of their apparent abundance: perch, blunt-nosed minnow, straw-colored minnow, blue-gill, common The following accounts of the habits and habitats of each sucker, whitefish, common sunfish, large-mouthed black of the thirty-one species of fish obtained is a summary of bass, pike, least darter, rock bass, wall-eyed pike, yellow the field work of the party during the summer: catfish, common bullhead, golden shiner, black-chinned FAMILY Salmonidæ. minnow, Johnny darter, blue-spotted sunfish, Cayuga minnow, Etheostoma iowæ, and barred killifish. 1. Common whitefish, Coregonus clupeiformis (Mitchill). This species is rated by many people the best of fresh- The species of fish that may be considered rare or water food fishes. It was found apparently abundant in uncommon are listed also in the order of their apparent Walnut Lake, where it was possibly native, since Mr. abundance: chub sucker, tadpole stone-cat, Lepomis Frank Crawford, a farmer living in its vicinity, reported euryorus, common shiner, little pickerel, miller's thumb, that his father and Mr. Henry Grinnell caught these fish brook stickleback, Notropis anogenus, and chub or from the lake as early as 1840. Three plantings, horned dace. aggregating over 100,000 artificially propagated It will be noted that more than a third of the forms known individuals, were made by the Michigan Fish to occur in Walnut Lake are well-known food fish, some Commission as follows: 3,000 in 1874, 40,000 in 1878 species being prized for their excellent flavor and high and 60,000 in 1879. value as food, as well as for their gaminess when taken Habitat.—At present the whitefish is an abundant with rod and reel. These facts make the careful inquiry resident of the deeper parts of the lake, where there are into their habits the more interesting and important, since practically no plants except the microscopic one-celled it is fair to infer that these do not materially vary in other algæ. It does not seem to visit the pond-weed zone to places where the same species are found. any extent, since but three of the 47 specimens taken were captured in that region, and those were found METHODS OF FISHING. where the water was about 20 feet deep. A single specimen was taken in water about a foot in depth near Although good sized individuals of species most sought the shore of station 3, on the night of April 18th. As after for food and sport abound, yet Walnut Lake is pointed out below, all of these visits of the fish to the reported to be a poor place for fishing with hook and line. shoaler parts of the lake may be correlated with the The black bass, grass pike and wall-eyed pike, all movements of the organisms used for food. excellent game fish, are common, but few are caught with the hook, judging from the reports of the people Food and feeding habits.—One of the most important living in the neighborhood. Some attribute their failure in observations made relating to the white fish was that of this sport to the great numbers of small fish and crayfish its almost exclusive use of midge larvæ for food during in the lake. It is possible that this abundance of natural part of the year. The larvæ mentioned are small, food, combined with the facts that unattractive baits are reddish, worm-like insects from about one-half to two- used, and unfavorable fishing places are chosen, may thirds of an inch long, and are the young of the two- account for the poor success reported. A most winged midges which closely resemble mosquitoes, and pernicious and unwise destruction of the larger fish is which in the spring appear in vast numbers about many being carried on by methods of fishing contrary to the lakes and ponds. The young, or larval stage, is passed fish and game laws of the State. Illegal fishing, such as in the muck at the bottom of the lake. In early spring the by gill net and spearing, was not uncommon, and jack- larvæ begin to change to pupæ, and from the last two lights were often seen moving about on the lake on dark, weeks of April to early summer seek shallow water, and still nights in the spring. In the spring fish were emerge as the adult, winged midges; these, after the frequently caught by us with spear wounds thickly eggs are laid in the water, soon disappear. covered with water mold, and fish dead from the same During early spring, and until June 2, when fishing in cause were often found. Spearing is particularly deep water with the gill net was suspended, the disastrous to the more important fish, since the grass stomachs of 30 out of 38 specimens of whitefish taken or pike, black bass and white fish resort to shallow water to found dead were examined. These were all large fish, breed, and not only the breeding adults are reduced in from 14 to 20 inches long, and weighing from 1½ to 2½ numbers by spearing, but the eggs and young are left pounds each. Eleven had no identifiable food in the unguarded and fall prey to numerous enemies against stomachs, and one had but a few mollusks shells. In the which, in the case of the bass at least, the old fish in part remaining 19, midge larvæ and pupæ were by far the protect them. most conspicuous and abundant material, constituting a The practice of spearing ought to be stopped, since the large part, or in a number of cases the entire, food mass. laws against it are based on sound biological principles, Several of the fish in the last lot had 200 or more midge which must be observed if the fish are to maintain larvæ in their stomachs, and one speared near shore in themselves in present numbers. a foot of water contained 200 pupæ. Larvae of Sayomyia, Sialis, and other insects, mollusks shells, and

Annual Report for 1907 / Walnut Lake – Page 1 of 66 in a few examples fish remains, constituted a small part bottom, (c) temperature of the water, (d) force and of the food in each of these stomachs. It appears that at direction of the wind, (e) breeding impulses. this season the whitefish are bottom feeders, since the (a) Food.—This is apparently an important factor in midge larvæ are probably found only at the bottom, and directing movements to the shoals, as indicated by the appeared to be most abundant in the deeper parts of the numbers of minnows on the shoals bordering the lake. The pupæ seek the shoaler water, and, as the fish marshes of the east shore (station 46), in the spring, taken in the pond-weed zone and on shoals had been when the midges were numerous there. An examination feeding on these, it is probable they were in shallower of stomachs at this time showed that midge larvæ and water seeking their favorite food. adults were then the chief food of these fish. After the In August, after two months’ disuse, the gill net was set latter part of May, when the midges became scarce, the again in deep water for a few days, and 9 additional fish, fish also became much less common on these shoals. weighing from 1¼ to 2¼ pounds were caught. An Minnows were also usually abundant about the nests of examination of these specimens showed that there had larger fish on the shoals, and were often seen eating the apparently been an entire change of food since early eggs and young, showing that they were probably June, for these fish had eaten no midge Iarvae, but had attracted to the shallow water by the presence of this been feeding exclusively upon small entomostracans of food. the genus Daphnia. As the masses of this food found in (b) Character of the bottom material.—Minnows were the stomachs were clean and free from dirt of any sort it more often seen on shoals with gravelly bottom, or those was inferred that the entomostracans had been taken supporting a good growth of plants. This factor is from above the bottom. undoubtedly closely related to (1), for such shoals Breeding habits.—The field season closed before the certainly furnish more fish food than those with marl breeding time of the whitefish, but the farmers on the bottom, or those with scant vegetation. vicinity of the lake reported that the fish visit the shoals (c) Temperature of the water.*—While variations in the at the east end in large numbers in November, at which temperature of the shallow water were marked, and an time they are caught by spearing. The visit to shallow attempt was made to correlate them with the movements water at this season is undoubtedly for the purpose of of the minnows, the data obtained were insufficient to spawning, and the gravelly shoals of stations 46 and 49 establish any relationship, especially as this factor was presented conditions similar to those in which the very difficult to separate from the others. Certain species is known to spawn in other waters. The observations, however, seem to indicate that minnows reproductive organs of most of the specimens studied gathered on those shoals where the water was warmest, were in a well-developed condition. No small fish were as shown by the following data: taken under a pound and a quarter in weight, which was probably due to the large size of the mesh of our gill net. From the evidence obtained it seems very probable that the species does breed in Walnut Lake, and that those examples caught were probably not those planted by the

Fish Commission from 25 to 30 years ago (see table of data given on another page.) *The observations on the effect of temperature and wind upon the movements of minnows were made by Mr. E. L. Michael, and most of FAMILY Cyprinidæ. the data given under this head are obtained from his notes. THE MINNOWS. At station 3 on the same date the fish were seen moving towards, the part of the shoal where the temperature Minnows of eight species were found (some in great was 19° C., from places where it was only 17° C., and numbers), and the species are named in the order of over a bottom which was of a similar nature throughout; their apparent abundance: (1) blunt-nosed minnow, (2) it is doubtful if food conditions varied sufficiently to straw-colored minnow, (3) golden shiner, (4) black- account for the movement of the fish at this time. On chinned minnow, (5) Cayuga minnow, (6) common May 31st, from 7:30 to 9:30 in the morning, nine of the shiner, (7) horned dace, (8) Notropis anogenus. These barren shoals with similar bottom conditions were small fish were often found in great schools in shallow visited, and the results given below were obtained. water, especially during the spring and early summer, but the pond-weed zone seemed to be their permanent Table showing relations of minnow movements to water habitat. From this zone they migrated to the shoals in an temperature on barren shoals, on May 31. irregular and seemingly erratic manner; being common on certain shoals on one day and scarce or absent the next, or even a few hours later on the same day. The minnows were undoubtedly controlled in these movements by a number of factors of which the following seem most important: (a) food, (b) character of the

Annual Report for 1907 / Walnut Lake – Page 1 of 66 As shown by this table minnows were most common and spring, and must cause much mortality among the where the water was warmest. While making shoal-frequenting fishes. observations on the barren shoals, notes were also (e) Breeding impulses.—The minnows undoubtedly made on those covered-with plants, and the data collect on certain shoals, or certain parts of them, for obtained are given for comparison. spawning purposes, but to what extent is not known, as Table showing the relation of minnow movements to the there were but few chances to study the breeding habits water temperature on plant-covered shoals, on May 31. of these fish. Nests of the blunt-nosed minnow were common in shallow water where the bottom was gravelly, which may be taken as evidence that the breeding impulses must cause these minnows to come to shoals of this type. Economic importance of minnows.—Our observations

indicate that the minnows are used as food by the larger At these stations conditions were much more varied than and more important fish to but a very slight extent, as at those in the first set, and the food factor was very few of them were found in the stomachs of any doubtless more important in its influence. It is difficult to species examined. They were often found in company understand the absence of fish from station 41 at this with large black bass, sun-fish and bullheads, but in all time, but in the afternoon of the same day, when the cases this association seemed a peaceable one, for the temperature had risen to 25° C., minnows and other larger fish were never seen making attacks on the small fish were numerous here, and a large collection minnows, except to drive them away from their eggs or was made. young. Fishermen also report that fishing with minnows As a whole, our observations (extending from early April as bait in Walnut Lake is not attended with success. to June 1st) indicate that from early April to June 1 At least two species of minnows, the blunt-nosed and minnows were found most common on shoals where the the straw-colored, do much damage by eating the eggs water temperature was from 17 C. to 27 C. Furthermore and young of other fish more important to man. All the temperature of the water also seemed to affect the minnows feed on midge larvæ in spring, and these activity of the minnows for in the early spring, when the insects form the chief food of the whitefish, and an temperature of the water was only slightly above the important part of the diet of other useful species, so that freezing point, they were very sluggish. in so far as the minnows deplete the food supply of the (d) Force and direction of the wind.—These factors larger fish they must be considered as an unfavorable apparently affected the movements and distribution of factor in the environment of the food-fish. minnows, but probably through their influence upon the (2) The blunt-nosed minnow, Pimephales notatus temperature. It was commonly noticed that when a (Rafinesque). strong wind was blowing the water would become cooler along the windward, and warmer on the lee, shores of Habitat.—This is the most common minnow in Walnut the lake, and that at the same time minnows were Lake, being found on shoals of all kinds, and also in the usually most numerous near the lee shores. On May 29 pond-weed zone. Its visits to the shoals were somewhat it was noticed that minnows were common in a particular irregular, owing to the influence of the factors given part of station 7, which, it will be remembered, is a above, but it was almost constantly present where the shallow bay, nearly circular in outline, and with its mouth bottom was gravelly, and was more generally abundant opening to the east (see another page 18). At the time where there were submerged plants than where the the observation was made the wind was blowing from bottom was marly. During the summer it became much the northeast; producing currents towards the south side less common in shallow water than in spring, as did of the bay, where minnows were collecting. They could other minnows. be seen moving toward this area from all parts of the Food.—The food of this species varies very much, but station, following the currents so clearly that bits of paper consists chiefly of small organisms taken from the placed on the surface, moved in the same direction, and bottom, from water plants, and from the water. collected in the same place. Individuals were frequently seen feeding on the eggs of During the colder parts of the year, strong winds must black bass, Johnny darter, miller's thumb, and sunfish of destroy large numbers of minnows and other small fish three species. At station 23, on July 14, they were found which frequent the shallows, since they are unable to eating newly-hatched fry of their own species. The move freely at such times, and the waves caused by the contents of the alimentary canals of many specimens winds dash them ashore. On April 8th the waves, driven were examined during the spring, and from those by an easterly wind with a velocity of twelve miles an studied it appears that midges, in various stages of hour threw up a ridge of drift material in which were development formed the chief food of this species, in found on the next day many minnows, darters and small April and May. Besides midges, filamentous algæ, sunfish, some of which were still living when found. desmids, entomostracans, and, in one case, beetles Such winds are of frequent occurrence during the fall were found in the stomachs.

Annual Report for 1907 / Walnut Lake – Page 1 of 66 Breeding habits.—Many nests of this species were found Food.—The stomach contents of the specimens between May 22 and July 14, but it is certain that this examined in April and May were chiefly midge larvæ, interval does not include the entire breeding season. entomostracans and filamentous algæ. The eggs were always found close together, attached to Breeding notes.—On May 2, at station 40, a large, the flat, under surface of some object, usually a stone, gravid female of this species was seen several inches but more rarely a piece of bark, a sunken board, or a above the sand, in company with many smaller ones, fence rail. Each of these egg-clusters was guarded by a possibly males. She was apparently in the act of darkly pigmented male with pearl organs. The fish spawning, although no eggs were seen falling. The remained constantly in the hole beneath the eggs until water at this place was about a foot deep, and the they were hatched, but apparently did not attend the bottom hard and sandy, and covered with algæ. young after hatching. (6) Notropis anogenus Forbes. A nest, with the attendant male, was placed in an aquarium at our head quarters; the fish immediately This species was apparently rare, as only two went under the stone, stood guard as usual, and specimens were caught in the lake (at station 41 on May remained even after the minute young had hatched and 31); a third was taken at Orchard Lake on June 18. The swam away. A similar case was noted in the lake, species closely resembles the black-chinned minnow in where the male fish remained guarding the empty nest form and coloration, and has the same black margin to for more than a day after the eggs had all been hatched. the lower jaw, but its mouth is very much smaller. The Plate 58 shows a piece of bark found at station 35 on identification of the specimens was confirmed by Mr. R. June 24, with eggs of the blunt-nosed minnow attached, E. Richardson. Plate 56 a nesting place of the blunt-nosed minnow on (7) The black-chinned minnow Notropis heterodon the gravelly shoal of station 23 (a nest was under the (Cope). stone marked "y" when the photograph was made on May 20). Plate 57 is another view of a part of the bottom Habitat.—The distribution of this form was similar to that at station 23, where, on June 27, there was a nest under of the Cayuga minnow. It was usually quite common at the largest stone shown in the picture. stations where vegetation was abundant, as at 40, 54, (3) The chub or horned dace, Semotilus atromaculatus 41, and 7, and was also found at the east end of the lake, in the spring, when the midges were abundant on (Mitchill). the shoals. On the night of June 21, at station 23, it was The chub was very common in the outlet, but only a seen swimming near the surface over the pond-weed single specimen was taken in the lake, station 9. A few zone, apparently attracted by the searchlight used in were caught near the lake, in one of the small inlets in making observations. the swamp zone of station 40. The species bred in the outlet, and a number of nests and spawning fish were Food.—Specimens taken from the shoals in the spring found there on June 1st. had been feeding largely on the adult midges, the rest of the stomach contents being made up of filamentous (4) The golden shiner, Brama chrysoleucas (Mitchill). algæ and a few entomostracans. On July 16th, three out of four specimens taken at station 7 had only This species differs from the other minnows of the lake filamentous algæ in the digestive canal, and the fourth a in having a flat body, so that seen from above it appears few insects. long and slender. The largest individual seen did not exceed five inches in length. Breeding habits.—The only records obtained on the breeding habits of this species was the capture of three Habitat.—It was common in all places where there were gravid females at station 54 on June 16th. many water plants, but its favorite haunts were stations 40, 54, 41, 7, 26 and 31. It was also taken on the shoals (8) The straw-colored minnow, Notropis blennius of stations 46 and 49 in the spring, at the time when (Girard). other species were abundant there. Habitat.—This and the blunt-nosed minnow were the Food.—The stomachs of several specimens taken at most widely distributed minnows in Walnut Lake. Both station 46 on April 26 and May 21, were examined, and were common on the shoals, where they schooled midge larvæ and filamentous green algæ were the chief together, but the straw-colored minnow seemed to food-materials found. Seven examined between July 8 inhabit deep water to some extent, as shown by the and August 11 had been eating filamentous algæ, with following records: On April 8th a specimen was dredged which the intestines were distended. (with the triangle dredge) from the bottom in water from 20 to 30 feet deep. On August 13, about 25, small very (5) Cayuga minnow, Notropis cayuga Meek. light-colored specimens measuring from ¾ to 1¼ inches Habitat.—The favorite haunts of this fish were the plant- in length were taken from a large school of this species covered shoals of stations 40, 54, 41 and 7, where it was from near the surface in the middle of the lake. At abundant. In early spring a few specimens were taken station 3A this species was often seen with other on the barren shoals of stations 16, 46, and 49. minnows in deep water off the pond-lily zone.

Annual Report for 1907 / Walnut Lake – Page 1 of 66 Food.—The alimentary canal of the specimens taken in the fact that they were on their way to the outlet to lay the shoals at the east side of the lake, in spring their eggs at this time. The outlet is undoubtedly a contained principally midges in various stages of spawning place for those individuals which live in the development, with some entomostracans and lake, and April is apparently the month when they resort filamentous green algæ. This species was often seen to the stream in the largest numbers to breed. Ripe fish eating the eggs of other fish, and on May 24 a sunfish were caught in the lake as late as May 20th, but there egg was found in the intestine of a specimen taken in a was no evidence to indicate that the species spawned in sunfish nest. the lake, except that individuals were often found in pairs in the gill net. No young were seen in the lake, although Breeding habits.—Nothing definite was learned of the they were common in the outlet. Pearl organs were breeding habits of this species. Of 30 specimens taken present on the rays of the anal fin, and those of the on June 25, from the deepest water of station 31, 8 were lower half of the caudal fin of many of the male fish males with pearl organs in the form of minute granules taken in April and May. over the head and body. Food and feeding habits.—The contents of the (9) Common shiner, Notropis cornutus (Mitchill). alimentary canals examined were as follows: Four, Habitat.—This species was found to be common only in taken May 12th, had been eating caddice-worms with the south bay, chiefly at station 31 and occasionally at their cases, small bivalve mollusks, amphipods, some station 45. During the summer large individuals were insects and marl. Nine specimens taken in August, at often seen in these habitats, swimming either within a station 200 (in about 40 feet of water), had fed on few feet of the surface or in water from 10 to 15 feet nothing but midge larvæ, and the small entomostracan, deep. Daphnia. In one of these fish Daphnia, only were found; in two, a mixture of Daphnia and midge larvæ; in the Breeding habits.—Shiners were abundant in the outlet of other seven, only midge larvæ. It is interesting to the lake, where they were seen spawning in June. compare the food of the specimens taken in August with FAMILY Catostomidæ. that of white-fish caught in the same haul of the net; the whitefish were feeding upon Daphnia only, apparently THE SUCKERS. away from the bottom, while some of the suckers were (10) The common sucker, Catostomus commersonii feeding on midges at the bottom, and others on the (Lacepede). Daphnia apparently above it. The individuals of this species taken were very uniform (11) The chub-sucker, Erimyzon sucetta oblongus as to size and color, having an average weight of about (Mitchill). 2½ pounds. Their backs were almost black, sides Habitat.—So far as observed, this fish was limited to brassy, gradually changing to white below, and the lower places where the vegetation was abundant. It was noted fins were reddish brown in all the specimens studied. at stations 7, 26, 40, 54, and 41. At station 7 they were Habitat.—Judging from the numbers taken in the gill net, seen occasionally in small openings among the bottom this fish was very abundant, and seemed to be an plants, into the protection of which they would dart when inhabitant of water of from 15 to 40 feet in depth, disturbed. Because of their habitat, they were not easily although in April and May several were obtained at caught, and but few were obtained. station 225 in about 80 feet of water. Owing to the fact Breeding habits.—A few small specimens, about ¾ of an that they lived in such deep water, no direct observations inch long, were taken on June 16, at stations 26 and 40, were made on their habits, but a farmer who spears fish and on May 3rd an adult male with four pearl organs on through the ice in winter made the statement that in each side of its snout and many small ones on the anal winter immense schools of suckers, roving close to the fin was netted at station 40. Most of those seen were bottom in such numbers as to "make it look black,” were between 7 and 8 inches long. The larger fish of the lake often seen through spear holes in the ice. This fish was feed on this species to some extent, for, on May 13, the common in the outlet, where large specimens were caudal half of a large female containing many eggs was sometimes seen at night (with the searchlight) near the found in the stomach of a black bass. lake (station 1). A few were again noted in this habitat on the night of April 10th, and on a single night in the FAMILY Siluridæ. middle of April a dozen or more large specimens were THE CATFLSHES. speared in the outlet. Some days later the gill net was set in about 20 feet of water in the pond-weed zone of (12) The yellow catfish, Ameiurus natalis. (Le Sueur). station 3, in such a way as to intercept fish going from Description.—It is probable that this species is not deep water to the outlet, and when raised two days later distinguished from the common bullhead by most of the about 50 large suckers, averaging 2½ pounds in weight, people fishing in the lake. While the two species are were found. This was the largest catch of this species similar in form, the one under consideration has a made. broader head and a larger anal fin than the bullhead, Breeding habits.—The abundance of individuals in the and is distinctly yellowish-green in color, while the true pond-weed zone, just mentioned, may have been due to bullhead is almost black. Annual Report for 1907 / Walnut Lake – Page 1 of 66 Habitat.—The species was taken or seen at ten different at this time one or more would swim from every shoal stations, and seemed generally frequent in the pond- approached, where there were bulrush stems or other weed zone, from which it went into shallow water at plants remains, which afforded partial concealment. The night. Small individuals, under 4 inches in length, were largest number of specimens was taken in the trammel common in shallow water where vegetation was dense, net at station 54, which seemed a favorite shallow water as at stations 7, 41 and 40. habitat. Food.—The stomach contents of four specimens The fish caught in the lake were mostly between 12 and examined consisted of crayfish fragments, May-fly 18 inches long; the largest was a little over 2 feet long larvæ, midge Iarvae and pupæ, and other insect and weighed 3½ pounds. A still larger fish was seen, remains. which had been shot while spawning in a marsh near the edge of the lake, on April 2nd. It was a female, 28 (13) Common bullhead, Ameiurus nebulosus. (Le inches long, with very large egg masses, and weighed Sueur). 8¾ pounds. Habitat.—This fish was seen or taken at nine stations, Food.—Food was present in but nine of the many with the yellow catfish, and in about the same specimens examined. It consisted of a single perch in abundance. The two species were undoubtedly closely six cases; of two fish of the same species, about 3 associated in habitat and feeding habits. inches long, in another, and 3 darters in another. Food.—Like the yellow catfish, this species is an omnivorous feeder, and in ten stomachs examined, crayfish, small fish, mollusks, entomostracans, leeches, beetles, and the larvæ of Hexagenia, Heptagenia, midges and dragon-flies were found. Breeding habits.—One June 28, a school of small bullheads about a half-inch long, attended by two old ones 12 to 14 inches in length, was seen in water a few inches deep near the shore of station 4. At the approach of the observer the adults swam away, but returned to their charges several times in the course of two hours. (14) The tadpole stone-cat, Schilbeodes gyrinus. This is a small species of catfish, about 5 inches long, and was found in but two parts of the lake, stations 7 and 41 and the adjacent stations 3 and 37, where they were quite common in the dense vegetation of the shallow, almost stagnant water of the bays. Food.—The stomach contents of a specimen caught at station 7, on May 23, consisted chiefly of a mass of insect fragments. Breeding habits.—On June 26th, a fish of this species, 2⅜ inches long, with a cluster of eggs was found in an old tin can at station 35. The water at this place was three feet deep, and the bottom was marl. The eggs are shown in Plate 59. FAMILY Esocidæ. THE PIKES. (15) The little pickerel, Esox vermiculatus. (Le Sueur). A single specimen of this species was taken in the trammel net at station 36, on May 2. (16) The pike or pickerel, Esox lucius. (L). This is called the "grass pike" by fishermen of the region. In early spring, as soon as the ice disappears from the marshes, the pikes seek these habitats to lay their eggs, and are at this time much sought after by gunners. The species is very common, judging from the number of individuals seen in shallow water in the breeding season;

Annual Report for 1907 / Walnut Lake – Page 1 of 66 FAMILY Umbridæ. in 6; midge larvæ in 2; small fish in 1; May-fly larvæ in 1. Crayfish thus seemed to form the most important part of MUD MINNOWS. the food of this species in Walnut Lake. (17) The mud minnow, Umbra limi. (Kirtland). Breeding habits.—Four nests of rock bass, were found Habitat.—This small fish was common only where the at station 24. They were all in water less than two feet aquatic plants formed a dense growth in shallow water. deep, and on a marl bottom covered by a scant growth It was never seen swimming in open water, all the of bulrushes. The first nest was found on June 6th; it specimens found being picked from masses of plant was about 20 feet from shore, in about a foot of water, drawn from the bottom at .stations 40, 41 and 7. and was guarded by a large adult. No arrangement of the bottom material to form a nest could be seen, but in Food.—Of the four specimens examined for food, two the area guarded by the bass, among the small were taken in April and two in July. The food was about stoneworts which here, as elsewhere on the shoal, the same in all of them, entomostracans, green algæ, formed a dense growth, were some very young fish water mites, midge larvæ, Planorbis shells and about ¼ inch long. The parent fish was not frightened miscellaneous insect material being present. when the water-glass was placed above it, and was so FAMILY Poeciliidæ. bold that it would bite a hand placed in the water near it. On two succeeding visits made within a few days, this THE KILLIFISHES. fish was watching the young ones and showed the same (18) The barred killifish, Fundulus diaphanus. (Le boldness in their defense. Sueur). A second nest was found on June 12th, near the end of Habitat.—The killifish was seen at seven stations. It was the same shoal, in water 17 inches deep. This was in a most common along the east side of the lake, where, in shallow depression of two or more inches. The the latter part of the spring, it was associated with depression did not, however, differ from the rest of the minows. bottom (which was of marl and covered by small stoneworts), and showed no signs of recent disturbance. Food.—Four specimens caught at station 41, on May 10, The attending fish was about 10 inches long, and had no had fed on midge larvæ, water-fleas, and a small fear of the observer, being even bolder than the first amount of filamentous green algæ. The stomach described; it seemed very successful in keeping away contents of specimens from station 46, taken on May minnows. The young were not found on the next visit, 21st, was composed chiefly of midge larvæ, beetles, and but their presence was apparent by the actions of the water-fleas, and several that were caught on May 31st fish, and the empty gelatinous egg-cases fastened to the had been feeding on midge and May-fly larvæ. In stoneworts. Two days later a young fish ⅝ of an inch general, it may be said that these fish seemed to take long were found among the plants in the bottom of the the same kinds of food as the minnows with which they nest. The fish was still guarding this nest on June 16th. were found associated. On the latter date, a similar nest was found on another FAMILY Gasterosteidæ. part of the same shoal, in 17 inches of water. Many eggs were found attached to stoneworts in this nest. THE STICKLEBACKS. (21) The blue-spotted sunfish, Lepomis cyanellus (19) The brook stickleback, Eucalia inconstans Rafinesque. (Kirtland). Habitat.—But little information was obtained concerning Habitat.—This species was only found in the stagnant, the distribution of this species. Few specimens were duck-weed covered pools in the swamp at station 42. taken, and these were caught in a trammel net, chiefly from shoals where plants were abundant. They were FAMILY Centrachidæ. seen more often than caught, and are recorded from THE SUNFISHES. stations 26, 7, 41, 31, 15, 19 and 20, but none were ever taken from the pond-weed zone by the drag seine or (20) The rock bass, Ambloplites rupestris (Rafinesque). fyke net. In early spring individuals of this species were Habitat.—The rock bass was a very common species at often found dead in the water. Walnut Lake. It was often seen in shallow water, but Food.—Of eleven stomachs examined, crayfish were apparently the pond-weed zone was its principal habitat, found in seven and dragon-flies in three; other and it visited the shoals in search of food and breeding organisms found, but which were apparently of minor grounds. It was abundant on the bulrush-covered shoal importance, were leeches, small fish (including a small at station 54, and a number were caught in the fyke net sunfish), water-mites, and miscellaneous insect remains. collections made in the pond-weed regions of stations The crayfish seems to be the most common food of this 15, 12, 3, 6 and 26. species. Food.—The stomach contents of 19 individuals taken Breeding habits.—The first nest of this sunfish was between April 19th and June 26 were examined, and the found early in July. It was in water nearly a foot deep, following animals found: Crayfish in 10; dragon-fly larvæ and near the shore of the east end of the-swamp Annual Report for 1907 / Walnut Lake – Page 1 of 66 loosestrife zone of station 26. It consisted of a capsules were attached to the roots of the bulrushes, at depression about a foot wide and three inches deep in the bottom of the nest, where there were also newly- the black mud of the bottom, and was situated close to a hatched young. The parent fish was protecting the nest sedge clump. In the depression there were many sedge from numerous blunt-nosed minnows and several small roots, to which numerous eggs were attached (Plate 60). sunfish, which were waiting to attack the contents. In the ten minutes or so which it took the owner of the nest Above the nest was a large, dark-colored male, with a to recover from the fright of being taken from the water coloration so similar to that of the bottom that its almost and to return to the nest, one of the little long-eared motionless body could scarcely be seen; it was further sunfish from the attacking party rushed into the nest and concealed by the light-colored border of its dorsal fin, began to drive out the minnows and sunfish. This small which appeared like a blade of grass in the water. A sunfish and some of the minnows were caught, and one small female was seen to deposit eggs in this nest July of the latter contained four young fish like those of the 3rd, and when revisited on July 7th there were still a few nest. unhatched eggs in it. It was vacated before the 13th, for on that date neither eggs, young, or attending fish were The large fish was left on the nest, because it was so found; at that time, however, two other nests similar to it tame it was thought best to study its habits and were found within a few feet, each attended by a fish of photograph it, but on returning later it was gone, and the same size and coloration as the first, and in one of was not seen again, hence was not positively identified. these new nests there were minute young about 1-5 inch (23) The long-eared sunfish, Lepomis megalotis in length. (Rafinesque). During July a number of nests of this species were found Description.—This species is very much like the at station 4, which had the same general form as those common sunfish in general form and coloration, but described, but the eggs were attached to the roots of differs from it in having shorter dorsal spines, a more bulrushes. At this point the bottom was of marl, and the rounded snout, and, in many adults, long, conspicuous fish guarding the nests were, in all cases, much lighter in opercular flaps or "ears." It was by no means as color than those at station 26, thus harmonizing with the numerous in Walnut Lake as was the common sunfish, light color of the marl bottom; the fins had the same light with which it appeared to associate. markings as those of the fish at station 26. This species, in Walnut Lake, resembles the common and long-eared Food.—Three specimens, the only ones taken in spring, sunfish and rock bass in its habit of choosing shallows caught at station 54, on May 9, had all been eating May- for nesting, but makes a deeper and more conspicuous fly larvæ, dragon-fly larvæ, caddice-worms and leeches. nest. The attending fish was also found to be less Breeding habits.—The species was more conspicuous in restless than those of the other species, remaining summer than in spring, and, after June 15th, nests were apparently motionless over its nest, from which, found at stations 4 and 54. In the former habitat two however, it is much more easily frightened than are the typical nests were found on July 1st near substation 4a, other sunfish studied. When disturbed, it darts away into in the bulrush patch shown in Plate 62, and close to the deep water, and seldom returns to its post until the outlet of the lake. The water at this place was 14 inches object of its fear is gone. deep. The nests were shallow, nearly circular (22) Lepomis euryorus (McKay). depressions, exposing the bulrush roots, to which the eggs were attached. Highly colored fish with long, Habitat.—This is apparently a rare species in Walunt conspicuous, opercular flaps were tending these nests Lake, since it was found only at stations 31, 54 and (Plates 63 and 64.) possibly 4, while but one was taken in the first mentioned habitat, and only a few at 54. All of these (24) The blue-gill, Lepomis pallidus (Mitchill). specimens were caught in May. The single individual taken at station 31 was kept in an aquarium until June Habitat.—The blue-gill was by far the most abundant species of sunfish in the lake. Its principal habitat was 16, and photographed while alive (Plate 61). It was 6¼ inches long, which was about the average length of the pond-weed zone, in which it was common those taken. The determination of this species was throughout the field season. It also frequented the shoals, especially those of stations 7, 15, and 54, on made by R. E. Richardson. which, in the spring, many specimens were captured in Breeding habits.—On June 28 a sunfish nest was found the trammel net. in the bulrush zone of station 4, in 15 inches of water. It Food.—The stomachs of 18 specimens of this species was watched by an individual which, although not carefully examined, was probably of this species. It was were examined and, until the middle of May, caddice so fearless as to allow itself to be taken from the water worms, crayfish, midge larvæ and pupæ, and the larvæ for a moment, and a chance was thus afforded to see of Heptagenia, Hexagenia and Sialis, constituted the that it differed in a marked degree from the long-eared bulk of the food, the midges predominating. After that time, crayfish, grasshoppers, crickets, beetles and other sunfish, which it resembled in its coloration. The nest was a nearly circular depression three inches deep, in land insects, together with entomostracans were the the marly soil of the bottom. The gelatinous egg- chief articles of diet.

Annual Report for 1907 / Walnut Lake – Page 1 of 66 Breeding notes.—The breeding season of the blue-gill May 21, station 40, on sand bottom. was long. The first nests were found on June 4th, the June 3, station 26, on sand bottom. first eggs on June 6th, while young only one-fifth of an inch long were found at station 12 on July 7th. The June 14, station 24, on marl bottom, with scant bulrush species is gregarious in its nesting habits, and many growth. groups of from 9 to 15 nests were found on the barren shoals at stations 16, 3, 19, 23, 32, and 12, which were June 24, station 4, on marl bottom; few bulrushes about the nest. the chief breeding haunts. Groups of nests were also noted on the bulrush-covered shoals of stations 15 and July 7, station 20, on marl bottom, bulrush-covered. 24. (26) The large-mouthed black bass, Micropterus The nests were always found in water from five to six salmoides (Lacepede). inches to two feet in depth, and every nest was tended by a very shy fish, which was so timid that it was difficult Habitat.—This fish was a very common species, dwelling to get near enough to see it at its station. All of the nests chiefly in the pond-weed zone, but, in the spring, were of the usual sunfish type, i. e., circular depressions frequenting the shallow water with the sunfish. In May in the bottom soil. They were about two feet in diameter, and June it was almost constantly present in the shallow from which the material had been cleaned away to cove, station 7, and, during the same months, it was expose the bulrush roots, to which the eggs were frequently seen in the bulrush zone of station 15. It was attached. also a common occurrence on warm days to see a number of individuals swimming close to the surface of (25) The common sunfish, Eupomotis gibbosus deep water over the pond-weed zone. (Linnæus). At station 54, in the spring, specimens, seven or eight Habitat.—This was the second sunfish in point of inches or more in length, were common, and were often numbers in Walnut Lake. It seemed to have a greater caught in the trammel net. The largest specimen taken preference for shallow water than the blue-gill, especially was 17 inches long, and weighed 4¼ pounds. Besides in spring, when they were very common on plant- these larger fish, extensive schools of bass fry, an inch covered shoals. In the summer, they were seldom seen or so long, were occasionally seen in June, and in in such places, except where the bottom vegetation was August small bass 3 or 4 inches long were common on abundant, as at stations 7 and 41, where small plant-covered shoals, such as those at stations 7 and individuals, about three inches long, were usually 54. The numbers and uniform size of these fish indicate common. that they were hatched during the season. Food.—The stomachs of 32 specimens of this species, Artificial introduction.—Black bass have frequently been taken between April 13th, and August 11th, were placed in Walnut Lake by the Michigan Fish examined, and, while May-fly larvæ of the genera Commission. The latest introduction was in the spring of Hexagenia and Heptagenia seemed to be the favorite 1906, when several thousands, obtained from the Fish food, crayfish, amphipod crustaceans, snails, leeches, Commission, were planted. midge larvæ, caddice-worms, and other insects were all found in the contents. The midge larvæ were apparently Food.—Data on the food habits were gathered from the eaten only in small quantities. examination of the stomachs of 24 fish caught between April 11th and June 10th. Nearly all of those examined Breeding habits.—Like the blue-gill, the sunfish was had been feeding on crayfish, five had eaten one or found to be somewhat social in its nesting, but the nests more small fish, and one, taken April 28th, had in its were not placed so close together, nor in such deep stomach about 350 midge larvæ and pupa), besides water (usually between one and two feet only). The Sialis and damsel-fly larvæ. From these facts, it appears breeding-season extended from May 21st, when the first that crayfish are the most important food of this species nests were found at station 40, at least until July 7th, in Walnut Lake. when two females were seen spawning at station 20. Breeding habits.—Nests were found at stations 19, 20, The nests were shallow, circular depressions in the 7, 40 and 54, but most frequently at 54. They were shoals, extending down to the bulrush roots. The eggs placed on shoals, in from one to two and one-half feet of were attached to the bulrush roots, generally to one side water. The first nest was found on May 16, in the midst of the center of the nest. Each nest was guarded by an of a tract of water-milfoil plants, and in about 15 inches adult male, some of which were very shy, while others of water. It consisted of a circular mass of blackened paid little heed when observations were being made roots from which the soil had been removed, and upon near them. Some of the adults were even very fierce in these were fastened great numbers of light-colored, attacking intruders, while others would calmly watch the small but conspicuous eggs. Other nests, having about minnows help themselves to the contents of the nests. the same appearance, were found later among the A list of the stations where this sunfish nested is given bulrushes, with eggs attached to the cleaned roots of below, with notes on the character of the environment, these plants. and the date on which the first nest was found at each place. Annual Report for 1907 / Walnut Lake – Page 1 of 66 The nests were guarded by one, or sometimes two, fish. Food.—Only thirty-two stomachs of the many which In some instances the guarding fish was quite fearless, Were examined contained food; of these 13 had and could be approached near enough to be studied numbers of midges in several stages of development, carefully. Minnows were numerous in the vicinity of and 11 had crayfish. Other food material, in relatively most of the nests, and, if the guardians were driven small quantities, was found to include May-fly larvæ and away, would rush in and eat the eggs. The nests were a variety of other insects, besides snails, leeches and often deprived of their guardians by fishermen, who entomostracans. The few fry opened contained chiefly speared them at night, and such nests were soon entomostracans, among which were copepods and stripped of their contents by minnows. ostracods. Economic.—This is one of the best and gamiest of the Breeding season.—Perch were found breeding during fresh-water food-fishes, and from its size and abundance the latter part of April. On April 23rd in the pond-weed in Walnut Lake should yield excellent sport, as well as zone of station 15, about 400 specimens were taken in quantities of good food. It is hardly necessary to say the fyke net. Most of these were mature males, but that it should not be speared from the nests. there were four females, three of which were spent, while the fourth had eggs protruding from the body. FAMILY Percidæ. Gelatinous masses of eggs were also found in the net. THE PERCHES. These females were much larger than the males taken with them. Schools of very young perch, sometimes (27) The wall-eyed pike, Stizostedion vitreum (Mitchill). containing several hundred individuals, were very This species was reported to be common in Walnut lake, common in June and early July, especially on shoals but only ten were taken. These measured from 15 to 25 with much submerged vegetation, such as those at inches in length, and weighed from one to five pounds stations 7, 40, 26, 54 and 31. They were also observed each. in bulrush zones, and, less often, near the surface in deep water, several hundred feet from shore, in some Habitat.—Nine of the specimens obtained came from the cases as far out as station 200. pond-weed zones of stations 15, 6, 46 and 7, and the other one from the deep water of station 200. Economic importance.—The perch is one of the best of the smaller fish, ranking high as a pan fish, and if Food.—The stomachs of all these specimens were properly taken (with a light tackle) furnishes considerable examined, but were empty, except two. Of the latter, sport. Its numbers and hardiness make it a valuable one from station 15 contained a perch 8 inches long, and species in such lakes as the one under consideration. the other from station 200, caught on August 6th, contained five small fish, each about an inch long, which (29) The Johnny darter, Boleosoma nigrum seemed to be small straw-colored minnows, then very (Rafinesque.) numerous near the surface of deep water. Habitat.—This very interesting little fish was a common Breeding notes.—A ripe male was caught on April 26th inhabitant of the shallow water, ranging to depths of six from the pond-weed region of station 6, and two females or seven feet; beyond the latter depth it could not be with large and numerous ova were found in the gill net detected with the water-glass. While noted on barren on the same day, so it is probable that this date is and bulrush-covered shoals, and on those with much included in the breeding season of the species in Walnut submerged vegetation, such as stations 41 and 54, the Lake. barren shoals with gravel bottoms seemed to be the chief habitat. (28) The yellow perch, Perca flavescens (Mitchill). Food.—The few specimens obtained in late April had Habitat.—This is apparently the most abundant fish of been feeding on midge larvæ alone, or on filamentous Walnut Lake. It chiefly inhabited the zone of pond- green algæ, the same food which minnows, taken at the weeds, but was commonly seen on the shoals in two or same time and in the same place, had been eating. A three feet of water, either singly, or, as was often the specimen caught on May 21st had been feeding on case, in large schools. Like the sunfish and bass, it was midge larvæ and entomostracans, but several taken on more often seen in shallow water in the spring than in the next day contained only midge larvæ. the summer, during the day, but was seldom (except in the case of very young fry in the summer) found in less Breeding habits.—The eggs of this species were only than two feet of water. With the aid of a searchlight it found on the under side of small objects lying on the was found to be an abundant visitor to the shoals at bottom in shallow water. The many nests found were night, when large numbers of scattered individuals could under flat stones about the size of a person's hand, or be seen resting quietly on the bottom at various depths, smaller, a single exception was one that was placed during both spring and summer. The fyke net, set in the beneath the valve of a mussel shell which lay concave pond-weed zones of stations 3 and 15, often caught side down. from one to several hundred specimens after being The favorite breeding places were the gravel-covered, down about a day. marly shoals of stations 23, 49 and 45, and nearly all of the nests noted between May 16 and June 19 occurred

Annual Report for 1907 / Walnut Lake – Page 1 of 66 in these places. These nests were each guarded by a THE FLORA. black-pigmented male, which was tireless in his attempts BY C. A. DAVIS. to drive away the numerous blunt-nosed and straw- colored minnows which were trying to get at the eggs, In an investigation of the character of the one upon but his small size prevented the darter from injuring the which this report is based, it is impracticable to cover intruders, and they gave him little attention. Doubtless thoroughly all phases of the biology of any considerable the eggs were more protected by being covered than by part of the region around the spot where the intensive the energy of their guardian. studies center, or to divert attention too strongly from the main problem under consideration. Therefore, while the (30) Etheostoma iowæ Jordan and Meek. plant relations of the broader field furnish a theme of The habitat of this species appeared to be similar to that great interest, but little space can be devoted to it here, of the Johnny darter, but it was much less abundant. It and, so far as plants are concerned, attention will be was especially common in the shallow parts of the directed chiefly to the flora of the lake and its immediate shoals of stations 6 and 16. At the latter place just after surroundings, since the fish, the central objects of this the ice had left (early in April), numbers of them could be investigation, are directly affected by this. seen swimming out into the lake, from beneath the Relations of plants to animals.—Plants are the sedge roots which fringed the shores. After the first of organisms which stand between the highly specialized July it was not found on the shoals. and complicated animal world and the inorganic or (31) Least darter, Microperca punctulata Putman. mineral kingdom, converting the gases and mineral matter of the latter into substances which can be This is the smallest species of fish found in the lake. Its assimilated by the former. Plants, then, may be termed maximum length is given as 1½, inches, but none were the primary food of animals, even when these, as is the found in Walnut Lake that exceeded 1¼ inches. case with many fish, do not use them directly for food, Habitat.—In the spring the species was found on shoals for, if the history is traced back far enough, it will be having much aquatic vegetation, as at stations 7, 26 and found that there is one or more vegetable feeding 41. They were also common in the spring on the organisms constituting the intermediate step from the bulrush-covered shoals of stations 1, 15 and 4, but were mineral world to the animal. scarce at all times on barren shoals, a few only being Aside from this relation, plants furnish places of nesting, taken at station 49, late in May. Like most other species, of refuge, and of rest for fish, and a study of the Walnut the least darter practically disappeared from the shoals Lake records shows that the abundance of many fish in summer. Some were caught, on July 9th, in the pond- and their permanence at any station was largely weed zone off station 6, in water from 15 to 20 feet correlated with good plant growth. deep, and it is possible that the fish seeks this area in summer. Requirements of plants.—Before taking up in detail the flora of the lake, however, a brief statement of principles Breeding habits.—Nothing definite was learned of the governing the distribution of plants over even the most time of spawning or other breeding habits of this limited areas, may not be out of place. species. During May, pairs were often seen with the individuals united in what may have been the spawning All green plants require for their growth and position, the female resting near or on the bottom, and development, light, heat, water, the gases, oxygen and the male above. No eggs were seen, but this may have carbon dioxid, which they get from the air, and soluble been due to their minute size. Males were also seen mineral salts, obtained primarily from the soil, with the chasing females at this time. water taken in by the roots. FAMILY Cottidæ. Adaptation of plants.—The absolute amount of these required by each species may differ, as may also their (32) The miller's thumb, Cottus ictalops (Rafinesque). powers of resistance to unfavorable deprivation or Habitat.—This fish was very common in the outlet, but excesses of some of them, hence we find plants growing only two specimens were caught in the lake. Both of in almost every kind of habitat, where all of these these were seen on gravelly shoals, one at station 49, essentials are found, and presenting peculiarities of and the other at station 13. structure or form, which seem to fit them for the particular environment in which they occur. It is said of Breeding notes.—The specimen noted at station 13 had such plants that they are "adapted" to the conditions a nest beneath a small stone on an area of stony bottom under which they grow. such as was used by the blunt-nosed minnows, for nesting purposes. The eggs were fastened to the under Thus we find plants which grow in very dry places side of the stone, which is indicated in Plate 56 by the provided with extensive, wide-spreading root systems, mark x. with relatively small leaves protected from loss of water by a thick epidermis, covered densely by hairs, scales, wax or other forms of covering, or, as in some desert plants, the leaves themselves may be wanting. In like manner, plants growing in shaded places often have Annual Report for 1907 / Walnut Lake – Page 1 of 66 large, broad, thin leaves, and, to increase the light- water, thus avoiding some of the difficulties of absorbing surfaces, green bark on their branches. submergence. Law governing plant distribution.—Since the Factors controlling plant distribution in a given lake.— requirements of the factors essential for plant growth are The distribution of these types of species must be limited absolute, and if one only of these falls below the to those parts of a lake where they find favorable places minimum amount needed by a plant to maintain itself, it for the growth of their underground parts (roots and perishes, it follows that plants unable to find all of the stems), and to those from which, after they are conditions necessary for existence in their environment established, they can grow upward to a place where must give place to those which can. This statement may sufficient light and heat reach their leaves to enable be illustrated by the commonly observed fact that, if the these to carry on their work of carbon assimilation. Most water supply in the soil of a field decreases below a plants living in water, or wet places, propagate certain amount, crop plants cease to grow, and, if the extensively by underground stems, which radiate unfavorable conditions continue, the plants die. All other horizontally from the established part of the plant. They conditions may remain favorable, but the failure of this are thus able to take possession of the lake bottom over one is effective in destroying the plants. On the other large areas, and to such depths as the species hand, at the time when one set of plants may perish, extending its range in this way is unable longer to get another set, because of a lower limit of tolerance, may enough heat and light, or is forced to meet other not be injured at all, but may even flourish, a state of unfavorable conditions. affairs sometimes seen during drought on cultivated The lake a desert.—Since but few species, and still lands, when weeds cover the ground, though the crops fewer orders of seed-plants can tolerate aquatic are dried up. Again, the presence of an excess of water conditions, the flora of lakes is monotonous, and in the soil may drive from it the air necessary to keep the consists of great numbers of individuals of few types; in roots of most land plants alive, and thus many species other words, the lake is like a desert in that it usually has which might find all other conditions favorable are kept a sparse flora of highly specialized plant forms, which from very wet habitats, so that in marshes, where the differ radically in structure and form from the plants of soil is saturated with water, there are relatively few the higher lands adjacent, and have slight relation to species of plants. It must also be apparent that if a them. single unfavorable condition for growth reduces the number of species, two such conditions will reduce the Reasons for zonal arrangement of plants.—Water and number still more, so that there are a great many less marsh plants because of the lack of competition with plants which will live with their leaves and roots other more aggressive forms, and because of their habit submerged than if the roots only are below the water. of spreading below ground in soil very favorable for this purpose, will usually arrange themselves about the The flora of a lake and its immediate surroundings, shores of the lake in about the order in which they can therefore, must differ to a marked degree from that of the endure submergence, so that, if the slope is uniform and highlands in its vicinity, not only in species, but in the gentle, and the soil all of the same nature, the plants will number of species, which will be much fewer than occur form a series of rings or zones, of greater or less width, on the uplands, in the kinds of adaptations to conditions according to the steepness of the slope of the bottom, of growth, and in other ways, but especially in the being wide if the slope is gentle, and narrow if it is steep. number and simplicity of associations found. Above the water level of a lake, on those shores where the soil is Invariable order of the zones.—Each one of such zones simply wet, there will usually be more kinds of plants will be characterized by the dominance of some plant or than are found growing in the water, because there are group of plants, so that it is easily differentiated from fewer necessary factors of growth affected, and until a others and may be given a distinctive name, and while certain optimum condition for rooted plants is reached, species may vary, and any zone may be wholly or in part for practically every inch which the land surface is raised wanting from a given lake, their vertical order of above the water level, there is an increase in the number occurrence is invariable when they are present. of plant species which will grow on it and in the Limits of the different zones.—Beginning in the deepest complexity of the associations into which these group water, the larger and more highly organized plants are themselves, absent, if the depth is more than twenty-five or (very Types of water plants and their associations.—Where rarely) thirty feet deep. Microscopic algæ are found at the soil is covered by water, within the margin of the lake the bottom in water more than thirty feet deep, and the itself, as has already been suggested, more than one stoneworts, closely related to the algæ, frequently occur factor of growth is different, and unfavorably so, from at depths of thirty feet or more, if the water is very clear. that of the normal environment of land plants, and we Seed plants of the submerged types, especially the have fewer seed-plants and simpler associations. In the pond-weeds, begin to appear sparsely in water about aquatic environment, some of the more highly organized twenty-five feet deep, and are the only ones visible until plants grow entirely submerged, some send their leaves the water is about 15 feet deep, when plants with floating to the surface where they spread out, and still others leaves, like the water-lilies, begin to show themselves, have parts of their vegetative bodies entirely above the and characterize a zone which extends shoreward until

Annual Report for 1907 / Walnut Lake – Page 1 of 66 the water is about 5 feet deep. Then if the soil zone, (11) White oak-hickory zone, (12) Black oak zone, conditions are favorable, these monopolize the part of (13) Scarlet oak zone, (14) White pine zone, (15) the lake where they grow, since the floating leaves Norway and Jack pine zone. crowd close together, and cut off the light from the water It must be noted, however, that with the type of soil and below, and prevent, or restrict, the growth of submerged conditions of temperature and rainfall postulated, the plants. In water 5 feet deep, plants with aerial stems, elevation of the top of the slope would have to be like the bulrush and other grass-like plants, with some considerably greater than any now existing in the region others, are able to establish themselves, and these may to have the zones of pine present. However, on a dryer cover the marginal region to above the water level about type of soil, the white pine still exists in a nearly pure the whole lake, providing other elements do not come in stand within a few miles of Walnut Lake, while near by, to interfere with the ideal conditions. The plants with "Pine Lake" indicates by its name the former closer aerial stems and leaves make a strong, dense growth proximity of this noble tree. where the composition of the bottom soil is favorable for this, and so cut off the light from the submerged types Reasons for variation from the ideal arrangement.—The and from those with floating leaves, so that these either ideal conditions for the complete development of plant take a subordinate position or disappear from the zones outlined above do not exist in Michigan, where association entirely. soils are rarely homogeneous, even over a single square mile, or for more than a few feet deep, and the slopes Zones above the water level.—Above the water level, are very irregular. The climate and rainfall are also sedges in considerable variety, ferns, and many other capricious, the latter often being reduced [below types of herbaceous plants, displace the bulrushes and minimum requirement of many upland species, for those forms which can grow in the water, and these in periods of years and through frequently recurring cycles, turn give way a short distance up the slope to the true thus profoundly lowering the ground water-level. This grasses, which often form a distinct zone. At about the causes even aquatic habitats to vary considerably, since same level, and frequently covering the same area with the water-level in lakes and marshes may be lowered the grasses, shrubs and sphagnum appear, and develop several feet below the normal for a period of years by an extensive zone and a complicated plant association. prolonged deficiency of rainfall, and thus temporarily In the landward edge of the last zone, coniferous trees, give chances for the plants of shoreward zones to like the tamarack, arbor vitæ, and black spruce form the advance lake-ward, opportunities which they first zone in the arboreal series, and this, in turn, is immediately take advantage of. At such times, shrubs replaced still farther shoreward by a border of the broad- will invade the sedge zone, and trees the shrub zone, leaved swamp trees from which, when natural conditions while the sedges and other plants more tolerant of water prevail, there is a gradual transition to upland forest, will make inroads along the zone left bare by the falling which presents a great number of species and many water of the lakes, from which the aquatic- forms different and complex associations. disappear. Ideal classification of the plant zones of the region about The plant zones of a lake affected by the soils of the Walnut Lake.— Not only will the vegetation in the lakes bottom.—Water and marsh plants are often restricted in and depressions have a zonal arrangement, but in the distribution, and form broken and incomplete zones region of southern Michigan in which Walnut Lake lies, if because of irregularities of the slope of the bottom, and ideal conditions of slope and soil exist, the entire flora the distribution of the soils on the bottom of the basin, as would be found to be in zones around the depressions. well as by the presence of soils whose situation or The ideal slope would be a gentle one; the ideal soil whose physical or chemical composition is unfavorable would be a homogeneous, moderately porous loam, to the growth of most types of plants. Unfavorable which would readily absorb and retain a sufficient factors such as steep or irregular slopes, exposure to amount of the annual rainfall to supply all plants with strong wave action, very compact, stony, or sandy soils, sufficient water for their needs. As the slope was or soils with too little plant food, or too much soluble ascended, however, the water would sink farther from mineral matter of a poisonous nature, are all likely to be the surface than at the foot, and the level of permanent present in those parts of lakes available for the growth of moisture would be deeper below the ground surface, the seed-plants. Any of such areas may be sterile, and thus making it difficult for the shallow-rooted plants to get cause interruption in the continuity of the zones. Again, sufficient moisture, so that those with deep roots would and by no means least in importance, species of the displace them. type necessary to give character to a definite area may As outlined above, and if uniformly favorable be absent, in which case the plants of another zone, temperature and rainfall conditions prevail throughout a usually the one from deeper water, may occupy the long cycle of growing seasons, the zones would be as place of those absent. follows: (1) The deep water zone of Algae and Application of principles to the flora of Walnut Lake.— Characeæ (stoneworts), (2) Pond-weed zone, (3) Water- The study of the contour map, Plate, 14 as already lily zone, (4) Bulrush zone, (5) Sedge zone, (6) Grass pointed out on a preceding page (5), shows that the zone, (7) Shrub-Sphagnum zone, (8) Coniferous tree slope of the basin of the lake is far from regular in those zone, (9) Swamp forest zone, (10) Hard maple-beech parts where vegetation can occur. In some places very Annual Report for 1907 / Walnut Lake – Page 1 of 66 steep slopes descend below the critical line of 25 feet, water-level this soil is usually barren, and above it, while over other large areas the water is less than 5 feet supports only a simple plant association. deep for long distances from the shores. However, the Black mud or impure peat.—This material is present in slopes from 5 to 25 feet are steep except in a few Walnut Lake in smaller amounts than any other. It is places, hence the zone of possible growth of the both chemically and physically adapted to the submerged seed-plants, and those with floating leaves, requirements of plants, being rich in proper mineral is quite narrow and also very unsymmetrical in its substances in an available form and in the necessary relations to the shore lines. The area which should be organic compounds, and is furthermore easily covered by partly emerged plants, bulrushes and penetrated both by roots and subterranean stems. It is sedges, is much broader and more conspicuous. thus capable of supporting a relatively large number of Relations of soils to zonal distribution.—Within the species and many individuals in a comparatively small irregular marginal area, soil conditions are quite diverse, space. Wherever this material is present between the and often consist of those types which are unfavorable critical depths for marginal plants in Walnut Lake, the to the growth of aquatic vegetation. The kinds of soil greatest variety and the largest numbers of plants are have been mentioned in the descriptions of the stations present. and need no further discussion here, except so far as is Peat.—Peat is composed of the same kind of material necessary to show how they affect the development of (but of slightly different origin) as the black mud into the zonal distribution of the plants. which it grades some distance below water level. It is Marl.—It will be seen by referring to the detailed brownish in color, coarser in texture, and generally has accounts of the stations, given on the preceding pages less finely divided mineral matter than the black mud. It that the chief bottom soil on the zone of possible is formed by the growth and partial decomposition of vegetation is marl. Marl is a chalky, white substance, those plants which live near, above or below, the water more or less granular at the surface, but very fine- surface, where the soil is so wet that the dead parts grained and compact below, which makes it physically a cannot dry up or completely disintegrate under the action poor substratum for the growth of the underground of the agencies producing decay. Peat constitutes the propagating stems of plants. Chemically marl is even substratum upon which grow most of the plants of the more unfavorable, since it is composed chiefly of sedge, shrub and coniferous tree zones of lakes. In calcium carbonate, with only traces of other mineral Walnut Lake it is chiefly confined to very shallow water, salts, and small and varying amounts of organic matter. or to areas now above the water level, and overlies beds This composition makes it an unfavorable soil for plants, of marl. since they require for their growth several other mineral Effects of aquatic and marsh plant associations on their substances besides those found in it. Besides the small habitat.—The growth of plants on any of the types of soil amounts or total absence of necessary salts, another mentioned above tends to produce an accumulation of unfavorable feature of the marl is the fact that the plant debris upon their surface, which is not removed included water is saturated with calcium compounds, under usual conditions, and thus slowly raises them which makes it toxic to the roots of some plants. As towards or above the water level. The ultimate end of shown by their failure to penetrate the marl. The marl as this process is an improvement of both soil and drainage a dominant soil is, then, capable of supporting only those conditions, since the decayed vegetable matter is rich in plants that can grow with a minimum amount of most of plant food. The slowly rising surface of the peaty mass the mineral salts essential to plant growth, and can also is eventually brought above the water, where it sooner or tolerate an unfavorable excess of calcium compounds. later dries and improves the substratum in texture Exceptions are to be found in those plants that have through more thorough decomposition, and makes it roots simply for holding them in place (if we have any much more habitable for plants. such) and are able to take the necessary mineral matter for their growth directly from the water through stems It is apparent that if an accumulation of the sort just and leaves. mentioned begins below the water surface, the original plant association which starts it will be displaced by As a matter of observation at this lake, as in many another, as soon as there is sufficient up-building to others, the flora growing on the pure marl is poor in improve the light and heat conditions, so that the species and individuals, but when there is a slight shoreward plants can advance upon the new territory. addition of organic matter, it seems able to support a much larger number of individuals and more species. This new association in its turn will be driven out, when it The stoneworts are generally present in numbers on has so modified the habitat by adding to the deposit that marl beds, although by no means invariably so. still another more aggressive group of plants can thrive upon it. Such changes, particularly in their early stages, Stony or gravelly soils.—The stony soil present in some take place very slowly, however, and it is only by parts of the marginal area of the lake is another type continuous and prolonged observation, or by the study of which is adverse to the growth of plants. Its chemical carefully made vertical sections of the deposit that the composition is favorable to most of the species, but its facts pointed out can be verified. That they exist is physical composition is so unfavorable that below the

Annual Report for 1907 / Walnut Lake – Page 1 of 66 evident when the theoretical considerations given above The sedge zone is characterized by grass-like plants, are applied to explain the observed facts. with usually triangular stems and a different arrangement of flowering and fruiting parts from that of the grasses. The limited areas occupied by the peaty formations at Several large genera and many species of plants are Walnut Lake do not offer special facilities for securing included under the general term "sedge," some of which evidence of the displacement of one plant association by grow on high ground, but the swamp and marsh types another, but the contact of the peat of the sedge are the most conspicuous members of the family. marshes with the underlying marl gives a record of the change from the simple associations of the stoneworts to Many other types of plants occur in the sedge zone, the more complicated one of the bulrush zone, and to some of which are larger and more conspicuous than the the still more aggressive one of the sedge zone. sedges with which they are associated; of these may be mentioned the swamp loose-strife and the cattail flag. The plant zones represented in the lake.—From the There are also at least two types of habitat represented effects of soil conditions and steepness of slope of the in the sedge zone at Walnut Lake, the wet marsh, bottom on the occurrence and abundance of seed-plants extending into water from 1 to 2 feet deep, and the moist in lakes, it is not surprising to find in Walnut Lake slope rising to the woods, or, more frequently, to the considerable areas of what should be available shallow zone of pasture grasses which come from the higher water but sparsely occupied by vegetation, and the land to meet it. These two were not carefully representative plants which characterize certain zones, differentiated, however, since both have the same either wanting entirely or present in small colonies in the general relation to the other plant zones of the lake. The most favorable soils, or, at best, forming a broken zone dryer parts of the sedge zone were well represented at interrupted by bare spots. Another apparent anomaly stations 23 and 32, while the wet parts are shown in found here is the extension of the stoneworts from the numerous figures as described below. The most deeper water practically over a large proportion of the conspicuous sedges of this zone were the Sartwell's, shallow part of the lake, which, except for the marl, water, slender and tussock sedges, the twig-rush, which presents a most perfect environment for aquatic plants. was unusually abundant, and a few spike-rushes, while Instead of having a dense growth of seed-plants with true rushes, the cattail flag, and swamp loosestrife were floating or partly emerged leaves, this area is largely frequent in some areas. Many other plants grew in this bare of noticeable vegetation, except for scattered association, but they were not recorded. Among the bulrushes, and it is only by close inspection that the figures accompanying the report, the following show carpet of stoneworts can be seen. That this condition is portions of the sedge zone and its relations to others. due to the adverse conditions presented by the marl as a Plates 16 and 19 show parts of the sedge zone of station soil is shown by the presence of the usual arrangement 16, where the beach is practically covered by sedges. of seed-plants, where the more favorable soil conditions The bulrush zone is almost wanting along this shore. are found, and also by the presence of a considerable Plates 19 and 20 show the sedge zone at station 32, admixture of either organic matter or debris with the where there is also a stony beach and a steep bank, at marl, where the higher or seed-plants grow in the foot of which the sedge zone ends abruptly. Plate 22 abundance. illustrates the flatter type of shore, on which the sedge Of the first nine zones, given in the list above, which zone broadens out into a marsh at station 46. Plate 23 might be present in the lake between the bottom and the is a spring-time picture of the shore of station 3, here the upper limit of that portion of the basin where soil sedge marsh is growing above the platform of marl, and drainage is sufficiently established to preclude swamp the sedges reach out to the edge of the water. conditions, only four are at all complete. These are the Plate 26 is a portion of the shore of station 16, where the deep water, including the stoneworts, the pond-weed, sedges border a beach composed almost wholly of the bulrush and the sedge zones. On the remaining five, shells; the plants are encroaching on the beach slightly. some are merely suggested and others are absent Plate 27 is another view, made in spring, of a portion of altogether. the sedge marsh of station 16, showing the sedge in The sedge zone.—It has been pointed out in another winter conditions and extending into the water. Plate 28 place that the slopes about the lake are relatively steep also shows the sedge marsh at station 6 in winter and well drained above the level of the water, and that condition. Plates 29 and 30 are views of station 15, they come down nearly to the water line, being showing the sedge zone in its relation to the landward separated from the margin of the water by a narrow shelf shrub and tree zones and the lake-ward bulrush zone. of flatter land around much of the shore, which has been Plate 31 is another portion of the sedge marsh at the somewhat widened since the outlet was cut. Owing to west side of the lake, and shows well the close these conditions, there is relatively little of the soil about relationship often existing between the sedge arid the the lake which is marshy, and, while there are quite strictly aquatic zones, when the depth of water is broad expanses of sedge marsh at the west side and in sufficient to permit. In the foreground is shown the places on the east side, the sedge zone, as a whole, is beginning of the artificial outlet where the water is deep narrow, although extending nearly around the lake. enough to permit the growth of water-lilies close to the sedge-covered banks. Beyond the outlet the bulrush zone merges into that of sedges. Plates 35, 37 and 36, Annual Report for 1907 / Walnut Lake – Page 1 of 66 especially 35, show the sedge zone modified by swamp Plate 47.—This is one of the best general views of a loosestrife; sedge plants are shown in the foreground pure growth of bulrushes, showing how sparsely they and at the right of the picture, where the sedges form a grow, and, when seen in masses, how completely they nearly pure stand. It will be seen that from this area the shut off from view objects behind them. sedge zone runs back toward the left behind the swamp Plate 17—A picture of the beach at station 23, with a few loosestrife, two-thirds across the picture. bulrushes growing on it, above water. It is evident from these and other illustrations that the Plates 29 and 30 show part of the bulrush zone of swamp loosestrife is a plant of the sedge zone, station 15. becoming dominant when present. Plates 43, 44, 45 and 46 show the sedge marsh at station 41, near the Plates 41 and 42 give views of the relation of the bulrush extreme southern end of the lake. Plate 52 shows and sedge zones in shallow water at station 7. another type of plant belonging to the sedge zone, although it sometimes invades the shallow water of the Plates 48 and 49 illustrate conditions on the margin of an bulrush zone; this is the cattail, which forms a narrow opening in the bulrush zone at station 54, where the zone against the swamp tree zone at station 40, and water-lilies grow around the opening and among the bulrushes. shown in the background of the picture. Plate 51 shows more clearly the relations of this plant at the same Plate 50 is the part of the bulrush zone at station 54 station, and it will be observed that lakeward of the where there were many nests of the black bass. denser part of the zone the plants appear scattered, and grow in the water. These may be advance guards of a The lake bulrush is apparently somewhat indifferent to general movement lakeward over the whole of the marl as a substratum, but grows larger and in denser adjacent shallows. Plate 53 shows another part of this masses where organic matter is present. As said station in which the cattail grows in small stools, in before, it is accompanied in such places by a much shallow water covered densely with the minute fronds of greater variety of associate plants, chiefly submerged a species of duck-weed and water-lily leaves. Plate 54 aquatics from the pond-weed zone and the water-lilies. gives an excellent idea of the relationship between the On pure marl the stoneworts are its only associate, cattail covered areas and other zones at station 40. except for very stunted pond-weeds. A resident of the Sedges are growing in the water on the left of the neighborhood, who was much interested in the history of picture. the lake, reported that a few years ago the bulrushes formed a solid zone entirely around the lake, so thick The bulrush zone.—As mentioned above, this zone is that a boat could with difficulty be pushed through it. one of shallow water, occurring in depths of about 5 feet This report is in part confirmed by the abundance of up to, or sometimes where soils are suitable slightly dead root-stocks and underground stems of this species above, the surface, merging into the sedge zone. The on most of the shoals where there are now very few bulrushes formed an almost continuous zone around the living plants. lake, although this zone was faint, or even broken, in places where conditions were adverse, as on barren The pond-weed zone.—This was a belt of vegetation shoals. It was clearly denned along the west shore at growing on the lakeward side of shoal water, between stations 15, 4 and 20, while at station 54 there was such the approximate depths of 3 and 25 feet; it thus ranged a dense growth of bulrushes that during the summer a from less than a hundred to several hundred feet in boat could hardly be pushed through it. width. The most conspicuous plant of this zone, and the one In no case were any except microscopic plants collected which gives it character was the lake bulrush, but from water more than 27 feet deep, and but a single associated with it were not infrequently found the white seed-plant, the water weed, from more than 20 feet. and yellow water-lilies, pond-weeds, hornwort, water The characterizing plants of this zone were the pond- milfoil, cattail, greater bladderwort, pickerel weed, and, weeds, of which several species were common and more frequently than any other, the stoneworts. The conspicuous, but it might well be considered the zone of bulrushes grew alone on marl shoals with the submerged plants, since but few of the types growing in stoneworts, and the other plants mentioned were only it have even floating leaves, the only parts to reach the found commonly where there was a layer of black, surface being the flowers. organic mud, or ooze, above the marl, in which the Several plants growing in this zone are also peculiar in plants rooted. Some species were never found except having but the slightest attachment to the bottom, or where this substratum was present. The maximum size even in some cases no roots (for example the hornwort of the lake bulrush (12 feet in length) was attained at the and bladderwort). Moreover, the vegetative parts, such edge of the shoal on the east side of station 54, where as buds and branches, of most of the plants of this zone the water was 5 feet deep, the extreme depth in which are able to live indefinitely when floating about in the the plant was found growing. Among others, the water with no root connection with the soil, and by virtue following figures illustrate the relations of this zone in of this trait are scattered widely about the lake. different parts of the lake: Besides pond-weeds, the seed-plants noted as abundant and generally distributed in this zone were, Annual Report for 1907 / Walnut Lake – Page 1 of 66 water milfoil (at least two species), water weed, hornwort and temperature conditions, readiness to migrate, and, and slender naias. Throughout this zone there was also what is more important, the absence of competition of an abundance of stonewort in both deep and shallow more aggressive types. water. All of the species of this association, because of The water-lily zone.—This was developed in but few the ease with which they propagate vegetatively, were places, and apparently only where the soil conditions often more common in shallow than in deep water, and were improved by the presence of organic matter. At made luxuriant growth in such places in the bulrush zone station 31, there was an area lakeward of the swamp as they established themselves, as noted above. But it loosestrife covered by the leaves of the water-lilies. was discovered that plants of these types dredged from They grew here in water from 2 to 6 feet deep, while water from 15 to 20 feet deep at station 3, on the 9th of below them there were some pond-weed sand a dense May were all of a bright green color and in active growth of stoneworts covering the bottom. Plates 33 condition, while individuals of the same species on the and 34 indicate the position of the water-lilies in relation adjacent shoals were all apparently dead, or had not yet to the marginal zone. started to grow. It thus seems as if the conditions for plant growth were better in deep water than in shallow, There was also a somewhat extensive development of at that time of the year. water-lilies at station 26, in much the same relationship to the swamp loosestrife as at station 31, except that At station 16, also, it was noted that, early in the season, here was a broader zone, extending out perhaps a there were no pond-weeds in water less than about 5 hundred feet to where the water was 8 or 10 feet deep. feet deep, but in July and August they became The bottom in this area, as noted elsewhere, was of conspicuous in water about 3 feet deep, and were black mud made up of decomposed plant remains. scattered, less noticeably, over the shoal in even shallower places. In the cove which constituted station Water crowfoot.—Practically a part of the water-lily 7, there was a strong development of the plants of the association at this station was a dense growth of the pond-weed zone, in shallow water and on a peaty white water crowfoot, which covered the water with a bottom. In the spring, stoneworts and an aquatic moss, carpet of delicate white blossoms about the middle of Hypnum, were the chief plants there, but during the early June. This area is shown in Plates 37, 39, and 40, part of May other plants began to appear, and during the which gives its evident relations to other plant groups summer white and yellow water-lilies, water weed, near it. White and yellow water-lilies were also present hornwort, water milfoil, a number of pond-weeds, at station 7 (Plates 41 and 42) both in shallow water bladderwort, and water persicaria covered the bottom, within the cove and in deeper water beyond the mouth. but, except for the water-lilies, did not grow quite to the Here again these plants were lake-ward of the surface. bulrushes, and grew in a substratum of peaty material a foot or more thick over the marl foundations. As early as July, at the south end of the lake, the water in the small shallow bay called, station 41 was practically Another extensive development of water-lilies was at entirely filled by water weed, stonewort, hornwort, water station 54a, where, as shown in Plates 47 and 49, they crowfoot and other plants, several of which were formed a rather dense growth along the margin of the prevalent in the pond-weed zone. The density of this bulrush zone. The soil of the station was a black mud mat of vegetation is shown on the right in Plate 45, just above a bed of marl. There was also an unusually wide in front of the sedge growth. The little spots on the water area of water-lilies at the west end of station 40, where are floating masses of green algæ with grasses they extended out from the shore for 200 feet to the entangled in them. The luxuriance of the vegetation at edge of the shoal. As seen in Plates 51, 53 and 54, the this spot is doubtless accounted for by the presence of water-lilies are here closely associated with cattail on the from 2 to 4 feet of soft, black mud in the bottom of the shoreward margin of the zone. The soil was chiefly a bay. soft, dark-colored mud. Another station at which the plants of the pond-weed These were practically all of the areas of these plants zone were found in quite shallow water, to the exclusion worth mentioning, and in looking over the record given of other types, was station 54a. This habitat was a above, it seems apparent, as stated at the outset, that circular opening in the bulrush covering of the shoal, and the water-lilies depend for their development largely had a bottom soil of partly decomposed vegetable upon the presence of a soil rich in organic matter, and matter, superimposed upon marl. The most abundant wherever this is present in shallow water, they are likely plants were stoneworts, reaching a length of 2 feet or to become conspicuous. more, and growing nearly to the surface of the water, water milfoil, hornwort, slender naias, greater Other zones.—The zones of plants shoreward of the bladderwort, while the white water-lilies grew along the sedge zone were studied in but a desultory way, since edge of the bulrushes, among which were cattails, and their relationship to the special work of the investigation was remote. It may be said, however, that there were less often the pickerel grass. fragments of a shrub zone where conditions were As has been pointed out above, the controlling factors in favorable, and Plates 35, 37 and 38 show portions of this apparently anomalous situation of these plants of this. The narrowness of the shelf about the lake, and the the pond-weed zone are, presence of favorable soil, light abrupt transition from this to the steep banks and Annual Report for 1907 / Walnut Lake – Page 1 of 66 clearing, are responsible for the absence of the shrub society. LIST OF PLANTS COLLECTED AT WALNUT No trace was found of the coniferous tree zone so LAKE. common about many of the lakes of southern Michigan. In the partially annotated list given below are included all The only conifers seen were the low junipers on the dry of the aquatic plants referred to in this report, and also bank of the north side of the lake, at station 32 (Plates the ones that we collected at Walnut Lake. It is not 18 and 20.) intended, however, to give an idea of the extensive flora The zone of broad-leaved swamp trees was chiefly of the region. represented at the northeast side of the lake, at station 40, and presented the usual characteristics of a wet Algae.* swamp forest of the region. White elm, black ash, soft maple, swamp white oak and other swamp trees grew in 1. Aphanothece stagnina (Spreng.) A. Br. Abundant in the wet soil, and cast a dense shade in which, on the summer at stations 7 and 41, forming, upon the bottom, stools formed by the crowns of the tree roots, muskrat blue-green gelatinous balls each an inch or so in houses and other elevations, grew a variety of shrubs thickness. and herbs; most abundant of the latter were sedges, 2. Anabæna sp. The material obtained was too grasses and the touch-me-not. The pools between the immature for the species to be determined. It formed trees were covered during the summer by duckweed and brownish masses on submerged plant stems at stations filamentous algæ. The conditions in this association are 40 and 37. shown in Plates 51, 52, 53, 54 and 55. At other places along the lake shore there were small areas where 3. Gloiotrichia natans (Hedw.) Rab. Species conditions invited an invasion of limited numbers of trees determination doubtful as plants were immature. Taken of this zone, but they were not extensive enough to form at station 23. a typical society. 4. Scytonema ocellatum Lyng. Station doubtful. Flora of the highlands.—As has been stated, this type 5. Spirogyra sp. A very common and conspicuous alga was not examined, in detail. It consisted principally of at stations 7, 40, and 41, where it formed a large part of farm clearings. The distribution of the trees, now left the surface scum. only in woodlots, indicates that the forest was formerly dense, and the trees of good size, the kind of 6. Mougeotia sp. Taken at station 40. association found depending upon the type of soil 7. Zygnema sp. Very common; occurring mixed with covering a given area. The heavier soils of the Spirogyra. moraines, the clay loams, where well watered, were covered by the hard-maple and beech, associated with 8. Vaucheria sp. Abundant at station 40, where it red, white and bur oaks, bass wood, walnut, hop formed tufts over the bottom. hornbeam and other trees of the mesophytic or moist, 9. Conferva bombycina. Taken in the ditch at station 7. drained soil type. In slightly dryer areas the hickories and white oak dominated, although in strong mixture 10. Draparnaldia plumosa Ag. Found at station 40. with some of the other kinds, and on sandy loams this 11. Batrachospermum boryanum Sirdt. Taken in the association passed into nearly pure white oak, then to outlet of the lake. black or yellow oak and white oak associations, and finally, on very dry sites, becoming a forest, with black 12. Dichotomosiphon tuberosus (A. Br.) Ernst. Taken at and scarlet oaks, of "the oak openings" type, on such stations 33 and 47. areas as the sandy, glacio-fluvial deposits, both south 13. Chætomorpha chelonum new species. Found at and north of the lake. station 26, on the back of a painted turtle. This has been Portions of numerous figures show the scanty tree described by F. S. Collins.† growth in the wood-lots and pastures in the vicinity of the *The specimens of algæ obtained were identified by Mr. F. S. Collins of lake, but few of them were made to illustrate specially Malden, Mass. this type of association, and show little detail. †Rhodora, IX, pp. 198-199.

Annual Report for 1907 / Walnut Lake – Page 1 of 66 Seed-plants.* Diatoms. 29. Broad-leaved cattail, Typha latifolia L. Common at On July 20 some bottom soil was dredged from a depth stations 40 and 54. Also formed conspicuous growths at of forty feet at station 200. Like all bottom material taken other places about the lake, as the patches in marshes from deep water, and microscopically examined, it was and in the sedge zone. found to contain many diatoms. Specimens of the 30. Bur-reed, Sparganium eurycarpum Engelm. Found bottom material were sent to Dr. H. H. Chase of Linden, in sedge zone at station 40. Michigan, who found ten species of diatoms in the material, as follows: 31. Floating pond-weed, Potamogeton natans L. *Common in shallow parts of the pond-weed zone of 14. Coccoei scutellum Ehrb. 20. Navicula radiosa Kz. stations 15, 24, 46 and others. It grew in patches whose 15. Cyclorella meneghiniana 21. Navicula radiosa acuta position was clearly indicated by the floating leaves of Kutz. Grun. the plants. 16. Cymbella gastroides Kutz. 22. Nitzchia linearis W. S. var. 32. Large-leaved pond-weed, Potamogeton amplifolius tenuis Grum. 17. Gomphonema Tuckerm.* Very common; the most abundant pond- acuminatum Ehr. 23. Surtella ovalis var. weed in the lake. angusta Kz. 18. Colletonema lacustre 33. Various-leaved pond-weed, Potamogeton Agardh. 24. Synedra ulna var. heterophyllus Schreb.* lanceolata K. 19. Melosina varians Ag. 34. Shining pond-weed, Potamogeton lucens L.* 35. White-stemmed pond-weed, Potamogeton Characeæ. prælongus Wulf.* Stoneworts.* 36. Eel-grass pond-weed, Potamogeton zosteræfolius 25. Nitella sp. This was found only in late summer. It Schum.* was abundant along the mouth of the outlet, and was 37. Slender naias, Naias flexilis (Willd.) R. & S. also noted in very shallow water near the shore at Abundant in the pond-weed zone in water less than station 23. fifteen feet deep. Also in shallow water at stations 7 and 26. Chara contraria A. A. Brown. The few stoneworts 41. collected were identified as this species, with the 38. Water-weed, Philotria canadensis (Michx.) Britton. exception of a specimen without fruits that seemed to be Abundant in the pond-weed zone, growing at all depths Chara fragilis. Stoneworts were very abundant in the in this region; also in shallow water at stations 7 and 40. lake, and they formed a rank growth in the shallower part of the pond-weed zone. On marl shoals small 39. Greater duckweed, Spirodela polyrhiza (L) Schleid. stoneworts were common, and were used by some of Abundant at station 40, growing with other duckweeds. the sunfish as places for the attachment of their eggs. In shallow, rather quiet water, as at station 41, 7 and 54, 40. Ivy-leaved duckweed, Lemna trisulca L. Abundant at the growth of chara was luxuriant. station 40.

*The specimens of these plants collected were determined by Miss 41. Lesser duckweed, Lemna minor L. Abundant at Ellen Bach of the University of Michigan. station 40. (See Plates 53 and 55.) 42. Pickerel-weed, Pontederia cordata L. Patches found Moss. at stations 26, 40 and 54. 27. Hypnum sp. Very common at station 7, forming a 43. Lake bulrush, Scirpus lacustris L. An abundant and thick mat over the bottom. A few fragments were also conspicuous plant characterizing the bulrush zone of the taken in our dredge at station 200. It is referred to as the shoals of a number of stations. Besides growing in the "water-moss" in this report. water, it was often found on wet ground with the sedges, sometimes forming distinct patches near marsh borders. Horse-tails. Bulrushes grew throughout the spring and summer, but only dead ones were present till about the middle of 28. Equisetum sp. Horse-tails formed a large patch in May, when the new growth became conspicuous. shallow water at station 40, where common sunfish were nesting upon the bottom among them. These plants The importance of the relation of bulrushes to fish life is were also numerous in the sedge zones of some other evident, when it is recalled that black bass, rock bass, stations, as at station 23. common sunfish and blue-spotted sun fish prefer for nesting the shoals where these plants abound to any others. They use the cleaned roots and root stocks of the plants, which were practically the only stable objects in the finely divided marl of the bottom, as points of attachment for their eggs. The stems also furnish Annual Report for 1907 / Walnut Lake – Page 1 of 66 shelter for the old and young, and doubtless prevent, to the ends of the branches with the roots which touch a considerable extent, the effect of wave action on the water is shown about the middle of Plate 66, while, in the nests, as well as furnishing places of refuge, and feeding background, and at either side, may be seen the well- grounds, for many types of food fish. established plants. See also report Mich. Biol. Surv., 1906, pp. 204-208th. 44. Water persicaria, Polygonum amphibium L. Occasionally solitary plants of this species were found in 50. Spiked water milfoil, Myriophyllum spicatum L. very shallow water on a number of shoals, including Abundant at station 54, where it blossoms freely in July those of stations 6, 7, and 31. and August. This is also a slightly rooted plant, and frequently has floats with no roots. 45. Large yellow pond-lily, Nymphaæ advena Soland. This species was abundant at stations 6, 7, 26, 4, 54, 41 51. Various-leaved water milfoil, Myriophyllum and 51. The plant is interesting because of its very large heterophyllum Michx. This plant grew somewhat underground stems or root stocks, and its habit of abundantly in the shallow water near the swamp developing submerged leaves early in the season before loosestrife border at station 26. It differs from M. the floating or emerged ones appear. The flowers of this spicatum in having well-developed, nearly entire, small plant are also often emersed on erect peduncles. leaves on the part of the interrupted flower spike above water. 46. White water-lily, Castalia tuberosa (Paine) Gregge. Common at stations 26, 40, 54 and 31. This species 52. The greater bladderwort, Utricularia vulgaris L. has an interesting habit of developing tuber-like Common at stations 54 and 7, and noted at other branches on the sides of the large root stocks, which, stations less frequently. A rootless, or rarely rooting when mature, break from the parent stem and, floating plant, with great numbers of small, bladder-like about, may find favorable lodgement and develop into enlargements on the divisions of the finely dissected new plants. leaves, the function of which seems to be to supply the plant with nitrogen by imprisoning the small aquatic *The species marked with a * were identified by C. A. Davis. animals which find their way into them until they die, and 47. Hornwort, Ceratophyllum demersum L. This species afterwards absorbing the nitrogenous compounds was abundant at all depths in the pond-weed zone, and resulting from their decay. The bladders have a very at other places even in shallow water as at stations 7, interesting and complicated structure for holding the 26, 54, and 41. animals prisoners, and a well developed system of internal glands which act as absorbing organs. For a Its usual lack of roots, and great power to propagate fuller account of this interesting type of plants see from any part broken off, as well as its indifference to Darwin.* weak light, makes this an exceptionally wide-spread plant in any lake where it occurs. *Darwin, C. Insectivorous Plants. 48. White water crowfoot, Batrachium divaricatum, (Schrank) Wimm. This plant formed a dense growth at station 26, covering the water at one time with the white, THE FAUNA OF WALNUT LAKE. emerged blossoms. It also occurred, although less BY T. L. HANKINSON. abundantly, at stations 7, 40 and 41 (Plate 40). As the principal purpose of this investigation was to 49. Swamp loosestrife, Decodon verticillata (L.) Ell. This inquire into some of the ecological factors making up the plant, found at stations 7, 41, 31 and 26, was one of the fish environment in Walnut Lake, the work on the most interesting ones found about the lake. It formed general fauna was purely incidental to that relating to the dense tracts at stations 31 and 26, and much less fish. The following discussion, therefore, makes no noticeable ones at the others. The plant grows in wet pretense of being more than a series of notes upon the soil or in shallow water, and is herbaceous, dying down animal forms which were observed while studying the each year to just above the water level, but is woody and fish, or upon those types having a close ecological perennial below it. Wherever it touches the water the relation to them. bark becomes very thick and great amounts of loose, very white, thin-walled tissue, called ærenchyma, Protozoa. develop. This is supposed to assist the plant to live with The one-celled animals noted here were such relatively its roots in the water. The long herbaceous branches conspicuous types as Arcella, Difflugia, Vorticella, etc., bend over, and where they touch the water send out seen while materials from the bottom (algæ, etc)., were roots and buds which grow into branches; the stem being microscopically examined. The shells of Arcella becomes woody and covered with the ærenchymatous were common among the fragments of algæ taken from tissue below the water and just above, and eventually the intestines of golden shiners in August, the fish establishes itself as a new plant at about the distance having undoubtedly picked up the protozoans with the from the parent that the branch reached. The branch plants to which they were attached, but, nevertheless, connection dies the first winter and the new plant the morsel of protoplasm constituting the animal must becomes independent. The drooping branches are have served as food for the fish. Ophrydium versatile O. shown in Plate 65, and the characteristic thickening near Annual Report for 1907 / Walnut Lake – Page 1 of 66 F. M. was the most noticeable protozoan in the lake, its Crustaceans. large, greenish, jelly-like colonies being so abundant The most common crustaceans were the upon some of the shoals, in early summer, that they entomostracans, which occurred as plankton or free- almost completely covered the bottom. In late summer swimming forms in deep water, and also about plants on this form was not seen. In the early part of August the the shoals, where they seemed especially abundant. In water and plants growing in it on station 15 were the latter habitat the smaller fish fed freely upon them, blackened by great numbers of a Vorticella-like and they formed a large part of the food of the fry of the protozoan, which was not identified. larger fish. In late summer the deep water forms of the genus Daphnia came to form apparently the entire food Sponges. of the white-fish, as nothing else was found in their No sponges were found in Walnut lake, either by the stomachs at this time of year. members of the party or by Professor N. A. Harvey, of The amphipods were less numerous, and only two the Normal College at Ypsilanti, who made a careful specimens were collected; these were identified by Miss search for them in the summer of 1905. Ada Weckel as Eucrangonyx gracilis Smith and Hyalella knickerbockeri Bate. Flat Worms and Round Worms. Crayfish were common, and many were found in shallow Parasitic worms were commonly found in the fish water in the early spring as soon as the ice had left. At opened for study, both in the enteric cavity and in the this season they were sometimes found attached to the body cavity. All of these organisms were preserved and gill net when it was drawn from near the bottom, where it sent to a specialist for identification. had been set in from 15 to 30 feet of water. About 40 specimens were collected from eight different stations Annelid Worms. during the spring and summer, and all were of the same species, Cambarus propinquus Gir., which is the most A small, few-bristled worm of this type, about an inch in common species in Michigan, according to Ortmann. A length, was found abundantly in material dredged from single specimen was taken in the lake with eggs the bottom in deep water. It was associated here with attached to the abdomen. Two other species, Cambarus midge larvæ, which it resembled in having a reddish diogenes Gir., and C. bartoni robustus Gir., were caught color; it was commonly found in white fish stomachs with on the outlet on May 2nd. Dr. Ortmann states that the midge larvæ. Unfortunately the material sent away for former has been reported but once before from the state, determination was destroyed in transit. The leeches viz., from Detroit by Faxon. Crayfish are eaten by a seen in the lake were collected and were determined by number of species of fish found in Walnut Lake, and Dr. J. P. Moore of the University of Pennsylvania as form a very important, if not the chief, food of the black follows: bass, rock bass and perch. 1. Glossiphonia stagnalis (Linn.) Insects. 2. Placobdella parasitica (Say). 3. Placobdella rugosa (Verrill). As in the case of other invertebrates, no 4. Eropdella punctata (Leidy). attempt was made by the field party to get Taken at stations 4, 7, 15, 32, 41 and 45. One was obtained from the stomach of a black bass caught at a representative collection of insects from station 15, on May 9. Egg cases of the species were the lake and its environs, and whatever found under stones at station 45 on May 20. time was given to these animals was 5. Dina fervida (Verrill). One obtained from the stomach devoted to working on those forms found of a perch caught at station 54. to be important as fish food. A special 6. Hæmopsis marmoratus (Say). One from station 20. report has been written upon the aquatic 7. Pisciola punctata (Verrill). Taken from the pectoral fin insects of the lake by Dr. Needham, and is of a black bass. published as 8. Macrobdella decora. This is the largest species of leech found. It was common at station 7, in the early part of summer. APPENDIX III. NOTES ON THE AQUATIC INSECTS by JAMES G. NEEDHAM. of this report. A large number OF WALNUT LAKE of specimens were also collected at the lake, in June, by WITH ESPECIAL REFERENCE TO A FEW Mr. A. Franklin Shull. The following are the more important notes made during the season: SPECIES OF CONSIDERABLE IMPORTANCE AS FISH FOOD. Annual Report for 1907 / Walnut Lake – Page 1 of 66 May-flies.—No very large flights of adult insects were description of station 3. See figures 12 and 13. These noted, although they were commonly seen about the were identified by O. A. Johannsen as Chironomus lake. The larvæ of Hexagenia were eaten in large niveipennis. It was, however, in the larval and pupal numbers by the common sunfish and to some extent stages that they were generally eaten by fish. During the also by other species. But few of these larvæ, probably spring and until about June 1st, when the fully-grown because of their burrowing habits, were found elsewhere larvæ were apparently more numerous and certainly than in fish stomachs. Heptagenia larvse, on the other more generally distributed in the lake than at any other hand, were found in large numbers on the lower time, they constituted the principal food-material found in surfaces of stones along the shore, and were also often the stomachs of whitefish. After this time few whitefish taken from fish stomachs. were collected; see tables page 54. Dragon-flies and damsel-flies.—While adults of many Sayomyia (Corethra).—This is a kind of gnat, the larvæ species of these graceful and showy insects were of which were quite common in deep water. They were numerous about the margin of the lake, larvæ were taken with midge larvæ from the deep-water stations, never found abundant. The few specimens of the latter and were sometimes found in whitefish stomachs. collected, came chiefly from the muddy bottoms in Beetles.—Parts of aquatic beetles were not recognized shallow water, as at stations 7 and 41. The larvæ, among the food material of any fish examined, but the however, were often found in the stomachs of rock bass elytra and other parts of terrestrial beetles were often and blue-spotted sunfish, less frequently in those of the found. common sunfish.

Grasshoppers.—These insects, while not inhabiting the Spiders. aquatic parts of the stations, were abundant in the sedge and other landward zones, especially in late summer, Little attention was given to these animals, and no facts and often fell into the water, where they were eaten by were obtained to show that they were at all closely blue-gills and doubtless by other species. The insects related to the fish life of the lake. None were found in were commonly noticed floating on the water surface, the food material from any fish, but, as they were and occasionally a fish would be seen to "turn up" and commonly seen running over the water surface near capture one. shore, they were doubtless occasionally taken by fish, and the negative data have little significance, in view of Aquatic Hemiptera or bugs.—These did not appear to be the soft bodies of spiders, and the small numbers of common, and but few species were collected. Among stomachs examined, as well as the hasty examinations the forms obtained were back-swimmers and a small made. Water-mites were common in shallow water, and relative of the giant water bug, Zaitha sp. Water striders some collections of them were made. were seen at times in quiet places near the shore, darting over the surface. Water-scorpions were frequently caught, and their eggs were common on Mollusks. water-lily leaves. Along the beaches, on warm days, While living univalve mollusks were scarce, except in toad-bugs were numerous. places where bottom vegetation was heavy, and rarely Neuropterous insects.—Both the adult and larval forms abundant even here, the empty bleached shells were were common. The most conspicuous of these were the abundant on nearly all of the marl shoals, sometimes adults of a species of Sialis, which appeared in numbers almost completely covering them over considerable on the bulrushes during the latter part of May, and their areas. There were also portions of the shore where egg masses were found attached to these plants in immense numbers of these shells had been cast upon quantities after that time. The larvæ were found in some the beach and sorted by the waves, according to size, fish stomachs. (Plate 26). An other beach of this sort formed part of station 44; from this a handful of shells was picked up Caddice-flies or case-worms (so called from the and sent to Mr. Bryant Walker, who found the following interesting habit which the predaceous larvæ have of species: building protecting tubes or cases of sand, shells, or other fragmental material, from the bottom on which they Limnæa desidiosa Say. Planorbis parvus Say. live). Cases made of shell fragments were often seen Physa sp. Valvata tricarinata Say. on barren shoals, in early spring, and these larvæ were (too young to identify). found in some of the stomachs of the fish examined. Amnicola limosa Say. Physa heterostropha Say. Many of these insects were collected by Dr. Needham Amnicola lustrica Pils. and are more fully discussed in his report. Planorbis bicarinatus Say. Pisidium (several species). Flies (Diptera).—The two-winged insects were common. Planorbis campanulatus The type of most importance as fish food (not only of this Say order, but of all the insects of the lake) was the midge, Chironomus. Adults of this form were exceedingly In late spring the following living snails were collected abundant in the vicinity of the marshy parts of the lake from algæ (chiefly Vaucheria): shore, during the latter part of April, as mentioned in the Annual Report for 1907 / Walnut Lake – Page 47 of 67 Valvata tricarinata Say. Planorbis parvus Say. small tadpoles, probably of this species, became abundant in the latter part of the month, in low, wet, Amnicola limosa Say. Pisidium sp. sedge-covered places. After this time the adult frogs On August 6th, small snails, Limnæa desidiosa Say, ceased calling and were not heard in May. were found in large numbers near the shore in very 4. Green frog, Rana clamitans Latreille.—An abundant shallow water at station 32. Bivalve mollusks, or frog, being noted chiefly during the late summer at "mussels,” were common, but not conspicuous; the stations like 7, 40 and 41, where submerged plants were smaller ones were sometimes found in shallow water, abundant, and where large specimens were sometimes but large ones seemed to be limited to deeper parts of found. Transformation stages were caught in the ditch the shoals, near the landward margin of the zone of at station 7, in July, and numerous small adults of the pond-weeds. These were apparently of one species, species, just transformed, were found on the wet beach which was identified by Mr. Walker as Anodonta grandis at the west end of station 23, in August, while their footiana Lea. Shells and fragments were sometimes tadpoles were common in shallow water on the same found in fish stomachs. Glochidia were found attached to shoal. each of the ten specimens of Johnny darters taken at station 49, on May 22, and also on the specimen of the Reptiles. same species taken at station 41, on April 27. 1. Garter snake, Thamnophis sirtalis (Linnæus). Amphibians. Common about the lake on both high and low ground. Incidentally to the work of studying the fish, the following 2. Water snake, Natrix fasciatus sipedon (Linnæus). amphibians were collected or noted: This form appeared to be rare, and only three were taken in the entire season. 1. American toad, Bufo americanus (Le Conte).—Toad eggs were abundant in the marsh (station 36), on April 3. Blue racer, Bascanion constrictor (Linnæus).—But a 12th and April 26th, and the animals were heard about single specimen of this snake, a large one 54 inches the lake until about the middle of May. long, was taken. It was caught in the timber zone of station 23, on May 16th. 2. Common tree-toad, Hyla versicolor Le Conte.—This noisy species was heard calling from the woods, 4. Milk snake, Lampropeltis doliatus triangulus (Boie).— orchards, farm-yards, and other places in the On August 24th a specimen of this snake was found at neighborhood of the lake. On May 16th, they were station 31. noticed abundant about a water-hole in an orchard a few 5. Snapping turtle, Chelydra serpentina (Linnæus).— rods from the lake, on the high ground south of the strip Specimens of this turtle were sometimes caught in the of timber forming part of station 23. The chorus of their fyke net, but the species was not common. The largest voices from this place could be heard for a long one noted was caught at station 6, on May 4th, and had distance, and they were doubtless breeding in the pool. a shell 11 inches long and 8 inches wide. 3. Leopard frog, Rana pipiens Schreber.—This was the 6. Musk turtle, Aromochelys odoratus (Latreille).—This commonest frog. It made its home chiefly in the was the most common turtle in Walnut Lake, and large marshes and sedge areas of the lake, and was not seen numbers were seen crawling on the bottom, both on on higher ground, and only occasionally in the lake. On shoals and in the pond-weed zone, especially during the April 13th a specimen of this species was caught in the spring. On June 25th, 91 eggs of the musk turtle were fyke net, which was set at station 200, several feet from found buried slightly above the water level in the walls of shore, and in about 40 feet of water. On the 18th of a muskrat house at station 40, and 70 were taken from April, eggs were found in the lake, where the water was another at station 7 (Plate 67). but a few inches deep at station 44, about 30 feet from the shore, while on the 20th a mass of eggs was found 7. Blanding tortoise, Emydoidea blandingi (Holbrook).— attached to an isolated swamp loosestrife plant, in five Taken with the painted turtle and musk turtle on the feet of water at station 31. From these observations it is shoal of station 16. apparent that the species enters the lake occasionally, 8. Western painted turtle, Chrysemys marginata but evidently not in numbers. (Agassiz).—Individuals were commonly seen, although In early April, immediately after the ice melted, leopard the species was not abundant in the lake. The stomach frogs became common and noisy in the marshes and of a specimen taken July 2nd, at station 26, was found about them, and the first eggs were found on April 8th, in distended with the leaves of some small-leaved pond- the marshy part of station 46, in water 8 inches deep and weed, probably Potomogeton pusillus L. or P. foliosus of a temperature of 8.5° C. These eggs were Raf. C. A. Davis, who identified the leaves, says unsegmented and were probably very recently regarding them, "It seems as if they had been scooped deposited. On the 11th and 12th of April this species up from a mass of drift material, such as sometimes and its eggs were very numerous in a small marsh at accumulates in shallows, rather than bitten off by the station 36, and individuals were also seen spawning at animal." With this material were found water milfoil that time. Frog eggs were often found during April, and Annual Report for 1907 / Walnut Lake – Page 48 of 67 buds, bunches of filamentous algæ, and fruits of the They were also found roosting among the rushes at slender naias. station 54. The stomachs of two caught in an insect net contained many insect fragments, chiefly those of Birds. beetles, but no remains of aquatic species were noted. These birds were sometimes seen upon the beach near No especial effort was made to study the birds of the the water edge. region. Aquatic forms and others that might affect fish life were noted, and a list of the species observed, with a 18. Tree swallow, Iridoprocne bicolor.—Often seen with few notes upon them are given below. Only the forms the barn swallow flying over the lake. that could be positively identified are listed. 19. Waxwing, Ampelis cedrorum.—Common along the 1. Pied-billed grebe, Podilymbus podiceps.—Throughout edge of the woods near the lake, at station 32, in early the summer, two were often seen in the vicinity of station summer. 26. 20. Long-billed marsh wren, Telmatodytes palustris.— 2. Loon, Gavia imber.—Often seen on the lake in late Commonly heard at stations 54 and 7 in early summer. spring. Mammals. 3. American bittern, Botaurus lentiginosus.—A few were observed about the lake at different times during the Muskrat, Fiber zibethicus (L.).—This is the only mammal summer. Often heard "pumping" on the marshy point on noted that could be considered an inhabitant of the lake. the west side of the lake. It was often seen swimming near shore, and its houses were common at stations 40 and 54. There was one 4. Least bittern, Ardetta exilis.—Occasional in late also at station 7 and a few at 41. This animal summer at station 7. undoubtedly has much effect upon the fish life, since it 5. Great blue heron, Ardea herodius.—A single removes quantities of vegetation from certain areas of individual was often seen at different places during the the lake, and in other ways disturbs conditions in the summer. shoal water. Observations made in July and August made it appear that a curious effect, noted in many 6. Green heron, Butorides virescens.—Common places where the bulrushes were dense, was produced throughout the summer. by the muskrat. Many rushes were cut off close to the 7. Black-crowned night heron, Nycticorax nycticorax water surface. This was first attributed to ice action in nævius.—One or two noted during the summer. the spring, but this cause was made improbable by the fact that rushes were being cut down in late summer in 8. American coot, Fulica americana.—One seen in late large numbers. A farmer boy living near the lake stated spring at station 12. that these animals cut off the young bulrushes a few 9. Greater yellow-legs, Totanus melanoleucus.— inches above the surface of the water, and gather them Common in May; often present in large flocks on the into rafts or platforms upon which they sit while eating. beaches. A large number of such rafts, as shown in Plate 68, were found at station 54. Some of the bulrush stubble 10. Solitary sand-piper, Helodromas solitarius.—One possibly produced in this way is shown in Plate 69. seen at station 40 on May 3. 11. Spotted sandpiper, Actitis macularia.—Common in summer. SUMMARY AND CONCLUSION. BY T. L. HANKINSON. 12. Kildeer, Oxyechus vociferus.—Common in large flocks, especially in late summer. In our opinion the results of the work done at Walnut Lake fall into two classes: (1) the determination of the 13. Belted kingfisher, Ceryle alcyon.—Common. fish life, and the habits of the species, and (2) the study 14. American crow, Corvus brachyrynchos.—Common. of the lake as a fish environment. The results of the first A nest was found in the timber zone of station 23. Often class are so diverse that no generalizations are seen feeding along shore of lake. advisable, and it only remains to sum up the environmental conditions presented by the lake, and 15. Red-winged blackbird, Agelaius phæniceus.— their effect upon the fish life. Walnut Lake may, in the Abundant and conspicuous about the marshes. terminology of Forel, be classified as a lake of the Especially common at stations 54, 40 and 7. temperate type and second order, as the temperature of 16. Swamp sparrow, Melospiza georgiana.—Common in the surface water varies widely both above (summer) marshes about the lake. Often heard singing in early and below (winter) the point of maximum density of summer. water (39.2° F.), and the bottom temperature undoubtedly undergoes slight fluctuations. These two 17. Barn swallow, Hirundo erythrogaster.—A very conditions are the almost necessary results of the abundant species throughout the summer. Hundreds geographic position of the lake in the temperate zone, often seen over the lake, capturing insects on the wing. and its depth. Annual Report for 1907 / Walnut Lake – Page 49 of 67 As may be seen from the contour map, the basin and a lack of oxygen, owing to the fact that all pelagic consists of a shallow marginal shelf whose outer margin forms, when they die, sink to the bottom and decay, thus has an approximate depth of 25 feet, and lakeward of tending to transform the proteids into simpler which the bottom drops rather regularly to 70 feet and compounds (the nitrates) with a consumption of oxygen. then in places to a little over 100 feet. Briefly, the shoals Owing to the dearth of cholorophyll bearing plants these are marl, and covered by a sparse growth of vegetation, nitrogenous compounds cannot be converted into but the margins, from depths of 5 to 25 feet, support a protoplasm again with a renewal of the oxygen in the rather luxuriant growth of aquatic plants; lakeward of this water, so that there is in general a dearth of oxygen until zone, the bottom has only a very scanty plant growth, the spring and fall circulation periods, when the aerated consisting principally of diatoms. According to Forel the water of the surface is mixed with the water rich in limit of extensive plant growth marks the limit of the nitrogen from the depths. As Prof. Reighard has pointed littoral region, and the almost plantless area within this out (see p. 23), there is, relatively speaking, zone should be classed as the abyssal region. On this considerable oxygen in the deep water of Walnut Lake basis the boundary between the littoral and abyssal during the summer stagnation period, so that we may regions in Walnut Lake is approximately marked by the expect that there is relatively little decomposition taking 25-foot contour. place on the bottom, a circumstance probably due to the fact that there is little plankton in the lake. The conditions that characterize the littoral region are: shallow water, a variable temperature approximating that The fish of the abyssal region of Walnut Lake are also of the air, a relatively good development of vegetation, a characteristic, the whitefish and common sucker being considerable abundance of invertebrates, abundance of found here apparently more than elsewhere. It follows light and oxygen, considerable wave action. The littoral from this that the whitefish is adapted to the conditions in zone, as has long been noted, is usually divided into a the abyssal region of this lake, as shown on a preceding large number of minor habitats by variations in the page (26), and possibly will do well only under these influence of the environmental factors such as wave conditions; at any rate, this hypothesis should govern action, soil composition, depth, etc. Where other factors future plantings, until the subject has been investigated are generally uniform the increasing depth off shore more fully. breaks up the environment into smaller units, as shown by the concentric zones of aquatic plants. Just how far the local distribution of fish corresponds to the habitats APPENDIX I. DESCRIPTION OF indicated by the plants cannot be determined until many more observations are at hand, but it is evident from our APPARATUS AND METHODS OF observations that the littoral region, supports a RECORDING OBSERVATIONS. characteristic fish fauna. According to our observations BY T. L. HANKINSON. it is the principal habitat of the smaller species, such as While the description of apparatus and other forms of the blunt-nosed minnow, straw-colored minnow, barred equipment and the methods used in recording killifish, Johnny darter, least darter, golden shiner, observations are of little interest to the general reader, it Etheostoma iowæ, Cayuga minnow, and black-chinned has been thought best to insert a short account of these minnow, and furthermore furnishes spawning grounds for the benefit of teachers and investigators who have for such larger fish as the sunfishes and bass. The fish special interest in this kind of work, and who may wish life is apparently adapted to these conditions. The small exact information concerning the apparatus and fish find protection in the vegetation, and it seems fair to methods employed. assume that the larger fish must of necessity spawn here, as the lower temperatures and lack of oxygen of The equipment may be classified under three heads: the depths could only retard the development of the (1) Collecting. eggs. The observation that in Walnut Lake the principal home of these species is the pond-weed zone, is an (2) Observing. interesting one. It may be that the more abundant (3) Recording. vegetation in this habitat affords better protection than do the barren shoals, or it may be that the shoals are so frequently unfavorable, owing to the variation in wave I. Collecting Apparatus. action, temperature, etc., that the fish occupy the relatively more stable conditions of the pond-weed zone (1) The Boat.—The boat used was about 16 feet long as a permanent habitat, only visiting the shoals. The by 4 feet wide; it was flat-bottomed and exceedingly well conditions in the abyssal region are quite the reverse of adapted to the kind of work done. It was borrowed from those in the littoral zone. The temperature must be the Michigan Fish Commission, through the kindness of rather constantly about that of the maximum density of Superintendent Seymour Bower and Mr. J. L. Brass, water, water perpetually calm, the light feeble, who sent it from the Bass Hatchery at Drayton Plains. vegetation scanty, pressure considerable, and the (2) Fyke nets.—The fyke net consists essentially of a animal life abundant. As a rule the abyssal region is long bag net, or funnel, distended by hoops, from the characterized by an abundance of nitrogenous matters mouth of which vertical nets (the leaders or wings)

Annual Report for 1907 / Walnut Lake – Page 50 of 67 extend on outward on both sides. The bag-net tapers through the large meshes readily, only to be entangled gradually to small size, and may have a trap towards the by the finer net within, which, because of its fulness, smaller end. Two nets of this type were used, the one pushes readily through the coarser meshes and forms borrowed from the Zoological Laboratory of the pockets which hold the fish securely. The trammel-net University of Michigan had a one-inch mesh, had a used was 100 by 6 feet; the mesh of the outer nets was funnel about 20 feet long and 3 feet high at the mouth, 8 inches, and of the middle one one inch; this was used and 40 foot wings. This net was very useful in collecting for shallow water, as it could be used regardless of the fish from shallow water stations. The second net of this nature of the bottom or the density of vegetation growing type was purchased for this work, and differed from the there. Plate 72 is of this net set at station 54. other in having the funnel but 12 feet long and 5 feet high, while the wings were each 60 feet long. The larger (6) Dip nets.—These are too well known to need end of the funnel and the wings were of inch mesh, but description. Several were used for collecting fish and the smaller end of the funnel was of half-inch. The chief other animals. use made of the net was in the deeper parts of the pond- (7) Set-line or Trawl.—This is a well-known device for weed zone. Plates 70 and 71 show these nets. exposing a larg-number of baited hooks for some time in (3) Gill net.—This is essentially a long, straight, places favorable for fish. It cone sists of a stout line, to rectangular net of large mesh, weighted on the lower which hooks with leaders of proper length are tied at side and buoyed above, so that when in use it stands regular intervals. In use, this line of hooks, properly upright in the water. When set it is sunk to the bottom, baited, is stretched at a suitable distance above the its position marked by buoys, and it catches the larger bottom and marked by buoys. From time to time the fish by entangling them when they try to get through the fisherman examines it, rebaits the bare hooks, at the meshes. same time taking off the fish caught. Such a set-line was rigged and set for several weeks at station 225, but Three nets of this type were available, but of these only with few results, a whitefish being the only fish caught. one was generally used. This was the property of the State Biological Survey, and was 300 feet long, 7 feet (8) Dredges.—This useful type of collecting implement deep, and of 2½ inch mesh. It was the only apparatus consists essentially of a bag-net, the mouth of which is which was a success in catching fish in the deepest held open by a metal framework, to which is attached a water of the lake. The other two gill-nets were borrowed rope for dragging the net along the bottom. Two of from the U. S. Fish Hatchery at Put-in-Bay, Ohio, and these, a "triangle dredge" and a circular one, were were 200 by 6 feet; one had one-inch and the other a ½- borrowed from the Michigan Fish Commission. The inch mesh. These were used but little. "triangle dredge," is so-called from the triangular shape of the frame to which the net is attached. The one used (4) Drag Seines.—This seine is a long net, sometimes was a bag-net of scrim, about 2 feet deep, the mouth of rectangular, sometimes tapering at the ends, which is which was held open by a heavy, equilateral triangular weighted at the lower edge and buoyed at the upper iron rim, the sides of which were about 2 feet long. The edges. Strong ropes are attached to the ends of the net, front edges of the rim were provided with saw-like teeth with which it is drawn. Various types of these seines are bent outward, so that when dragged along the bottom in use by fishermen, but all are used to enclose a larger they would stir up the mud and such organisms as were or smaller area of water temporarily, and then drawn. in it, so that some of them would be taken in the net. The drag net is usually set in shallow water and dragged The dredge was kept upright when in use by iron rods ashore along with such fish as are enclosed by it. Three each 3 feet long, extending backward from each angle of large nets of this sort and two small ones were used. the triangle, parallel with the direction of the net. This The largest was borrowed from the U. S. Bureau of was the dredge used most, and was efficient in getting Fisheries and was of inch mesh, 100 feet long, 12 feet large samples of bottom material and the small animals wide at the middle and tapering to 8 feet at the ends. A living in it. A second dredge, which was little used, had second net was the property of the State Biological a circular metal mouthpiece without teeth, and four bars, Survey, and was of inch mesh, and 60 by 12 feet. The like sled runners extended back from it. third large net was a minnow seine, purchased in the summer to make collections of the small fish in the pond- (9) Plant hooks.—These, as the name implies, are weed zone. This was of ⅜-inch mesh, 50 feet long, 12 hooks for dredging plants from the bottom in deep water. feet high, tapering to 8 feet at the ends. Minnows and They were similar to those described by Pieters*, and other small fish were caught in shallow water near shore were made as follows: by "Common sense" minnow seines, made of coarse Four large hooks of heavy, strong wire were placed in mosquito netting; two of these, 20 by 4 feet, and 8 by 4 one end of an iron pipe 18 inches long, at right angles to feet, respectively, were used. each other, and a piece of the same wire bent to form a (5) Trammel net.—This type consists of three nets ring in the other end, and the pipe was filled with melted fastened together at the edges, the outer two of large lead. A line was fastened to the ring, and the hook was twine and coarse mesh, the mid-one somewhat larger used for collecting plants from deep water being very than the others, so that it is loosely held in folds between efficient for the purpose, as shown by Plate 73. them, and is of finer twine and small mesh. Fish pass Annual Report for 1907 / Walnut Lake – Page 51 of 67 A small bag-net about 6 inches in diameter and 2 feet 3. Thermometers.—A series of standard chemical long was fastened to the hooks, so that it dragged thermometers, obtained from the Bausch and Lomb behind them to catch insects and other organisms Optical Company, were used in taking deep-water disturbed by the hooks, and some of the mud stirred up temperatures, and a Negretti-Zambra deep sea by it; this was a useful addition to the drag. The thermometer was borrowed from Professor A. E. Birge of combined apparatus was called "the hook and net drag." the University of Wisconsin, and used for a few days. (11) Birge net.—This was used but a few times in 4. Thermophone.—This instrument was purchased for making small collections of plankton. the investigation, but had been used only a short time at the opening of the season when it got out of order, and it (12) Soil sampler.—This was a tool similar in form to was late in the season before it could be repaired, so but that figured by Pieters†, and was made from a tin funnel few readings were made with it. and an iron pipe. 5. Anemometer.—A small portable hand instrument, (12) Walker dipper.—This name was given to a copper owned by the State Biological Survey, was constantly dipper of about a quart capacity, having a bottom of wire used to make observations on the velocity of the wind cloth, and a handle with a screw clamp by means of whenever other observations were made. which it could be quickly fastened to any convenient pole. It is the invention of Mr. Bryant Walker, who has 6. Aneroid barometers.—A pocket aneroid, the long used it in collecting mollusks in shallow water, and property of the Michigan Geological Survey, was used to who presented two of them to members of the survey obtain daily record of the atmosphere pressure near the party. There were very useful for making collections lake level. where the water was shallow. 7. Barograph.—This instrument also belonged to the (13) Trap lantern.—An acetylene bicycle lamp with Michigan Geological Survey, and was kept running funnels and reflectors, below which was a vessel continuously from about May 1st to the middle of August. containing potassium cyanide, was used to attract and capture flying insects at night. The apparatus was hung 8. Turbidimeter.—The standard candle turbidimeter, of to trees or posts, near the lake or the outlet, and left over the pattern used by the Bureau of Hydrology of the U. S. night. This lamp was invented by Dr. J. G. Needham. Geological Survey, was furnished by the Michigan Geological Survey, and used to measure the amount of (14) Sieve net.—This is a rectangular tray of heavy tin, turbidity of the water at various times. having a long handle running at right angles with the bottom, which was made of wire netting. It was used like 9. Colorimeter.—This also was of the type used by the a hoe in shallow water, and was made for Dr. Bureau mentioned above, and was a part of the Needham's use after a design of his own. equipment furnished by the Michigan Geological Survey.

*Pieters, A. J. Plants of Western Lake Erie. U. S. F. C. Bulletins, Vol. 10. Aquaria.—Four aquaria were borrowed from the U. XXI. Washington, 1901, pp. 57-79. S. Bureau of Fisheries and were used for making †Pieters, A. J. loc. cit., p. 58. photographs of live fish, for rearing insects, and for keeping aquatic animals which were under special observation. The aquaria were supplied with water from II. Equipment for making observations. a metal watering tank, elevated somewhat above them, into which the water was pumped from the outlet of the 1. Water glass.—This is a simple apparatus, consisting lake. The position of this tank and arrangement of the of a pane of glass set tightly into a deep frame which will aquaria are shown in Plate 74. keep out water. Of the four used, two were ordinary galvanized iron pails, with glass bottoms, and two were metallic trays, also with glass bottoms; one of the latter III. Equipment for making records. was 1½ feet and the other 3 feet square. 1. Field notes.—The loose-leaf system of records was These glasses were placed on the surface of the water, used, and the sheets for the day were carried in and by looking through them, the effect of waves, or aluminum holders, which were found convenient for the reflection and polarization, from the water was done purpose. The form reproduced below was used in away with. Under ordinary conditions of lighting objects recording observations at definite stations. 12 or 15 feet below the water surface could be distinctly seen. A wooden box with a pane of glass tightly set in the bottom will answer as well as the more expensive metal ones, and will furnish a means of obtaining a great amount of information regarding the habits of aquatic animals to any one living near a lake or stream. 2. Searchlight.—This was loaned by the U. S. Bureau of Fisheries, and was found valuable for getting records of fish in shallow water at night. Annual Report for 1907 / Walnut Lake – Page 52 of 67

2. Cameras.—A 4x5 reflex camera was used to make photographic notes to accompany the written ones, instead of sketches. For larger landscape work, a 6½ x 8½ and a 5 x 7 camera were used. For making pictures of living fish in the aquaria a 5 x 7 "graflex" camera was available on several occasions. Altogether several hundred photographs were made during the season, some of which are used to illustrate this report.

IV. Miscellaneous equipment. 1. Tents.—Two small tents, belonging to the Michigan Geological Survey were used for storage and field laboratories, for the rougher work. 2. Preservation methods.—The fish collected were preserved in formaldehyde according to a method used by R. E. Richardson of the Illinois Laboratory of Natural History. The fish were thoroughly hardened by leaving them in a 10% solution of formalin for a few days, after which they were transferred to a 2% solution for permanent preservation. Insects and a few other specimens were placed in alcohol, but relatively very little of this preservative was used. Plant specimens were either pressed or preserved in 2% formalin solution. Large milk cans were used for storage of fish specimens, and the usual forms of glass vials, bottles, and jars were employed for small and delicate material.

APPENDIX II. DATA ON STOMACH CONTENTS OF FISH TAKEN IN WALNUT LAKE. BY T. L. HANKINSON. The following tables, while not in any way pretending to give a complete account of the numbers of fish caught and examined, may give some indication of the food of the food-fish, especially the whitefish, thereby giving some information as to what is a proper habitat in which they will thrive. Other data regarding the same subject will be found in the section relating to various stations, with other similar facts which would not admit of tabulation.

Annual Report for 1907 / Walnut Lake – Page 53 of 67

Annual Report for 1907 / Walnut Lake – Page 54 of 67

Annual Report for 1907 / Walnut Lake – Page 55 of 67 A few species of great importance as fish food, however, received the greater share of my attention, and my APPENDIX III. NOTES ON THE observations thereon comprise the first part of the AQUATIC INSECTS OF WALNUT following paper, the second part being an annotated list of the aquatic insects observed, and the third part some LAKE observations made in cooperation with Mr. McDonald on WITH ESPECIAL REFERENCE TO A FEW a dipterous gall upon the submerged petioles of the SPECIES OF CONSIDERABLE yellow water lily. IMPORTANCE AS FISH FOOD. by JAMES G. NEEDHAM. I. THE IMPORTANT FOOD SPECIES. In June Prof. Reighard wrote me that the Survey at Professor Hankinson's detailed report on the food of the Walnut Lake was finding insects an important element in fishes of Walnut Lake, given elsewhere in these pages, the food of fishes there, and asked whether I could not demonstrates again the great importance of the larvæ of come myself or send some one to study them. Having midges of the genus Chironomus and of Mayflies of the no one to send at the time, and being greatly interested genus Hexagenia, and shows that fishes which forage in the matter because of former similar findings of my on rocky shores, feed to some extent also upon the own, I determined to go myself, if only for a little while. I larvæ of Mayflies of the genus Heptagenia. These was then on the point of departure for the meeting of the insects have several common characteristics. They all American Association for the Advancement of Science at have a very short period of adult life; during which no Ithaca, and I stopped off en route to spend part of three food is eaten: the mouth parts in all are rudimentary. days at Walnut Lake going, and a week, returning from The adult life of all is concerned solely with reproduction, the meeting. Of these ten days—June 26-8, and July 8- and they all leave the water with the sexual products 14, I was favored by accessibility of quarters to collecting practically mature. They all transform in open water, grounds, by good weather and good equipment, and leaving their cast off skins floating upon the surface, and especially by the intelligent aid of the two men in charge fly to some shelter on shore. They are all nocturnal or of the station work, Mr. T. L. Hankinson and Mr. Elmer crepuscular in their adult habits, and in consequence, McDonald. But even with these advantages, and with are very difficult of observation. the aid of additional collections made before my arrival and after my departure, it was manifestly impossible to do more than scratch the surface of the insect problem Chironomus. in a few spots. Aquatic insects are a great host, and This great genus of midges is represented by a there is none of them whose life history is not beset with considerable number of species at Walnut Lake. A few many unsolved problems. of the larger species that live in the deeper water are Both Director Lane and Professor Reighard recognized doubtless of most importance as fish food: for it is the the limitations and merely asked that I should proceed larger larvæ that are found in their stomachs. The with such collecting and observations as would be largest species of the genus, Chironomus plumosus, possible during my stay. The results are embodied in was common, and, finding there my first opportunity for the following pages. making observations on the habits of this species, I gave to it the greater share of my attention and time. I give a In company with Mr. C. C. Adams and the station staff I special account of it below, following this with some first visited all the collecting stations on the lake, looking general observation on the structure and habits of a out for the most favorable places for finding insects. number of others of the larger members of the genus. Then I made a hasty examination of insects collected by Mr. Hankinson from fish stomachs, to see which It may be said of the larvæ of the larger species of appeared to be the important species. These proved to Chironomus that they are the well known "blood worms," be, as usual, midges and May-flies, whose larvæ live in one lifts with a dip net out of the black bottom mud of water of some depth. any deep pool, an inch or less in length, cylindric, of a bright transparent red color, legless, save for a pair of The activities of the adults begin after sundown: so, at short prolegs at each end of the body, the anterior ones the lake, until dark or later, I spent every evening at the ending in a disheveled brush of soft hairs, the posterior exceedingly difficult task of observing the swarming and ones bearing slender double-arched claws, hairless save mating habits, and succeeded in filling a few gaps in our for two conspicious tufts of bristles on the end of the last knowledge of the more important species. I collected by segment of the body above and a few microscopic hairs day with a dredge in deep water, or with nets along about the head, living in thin-walled tubes of homespun shore. A single trap lantern, run every night, silk covered with adherent silt, and when torn from their supplemented the collections with tens of thousands of tube swimming with figure-of-eight-shaped loopings of specimens and a goodly number of additional species, the body, they are easily recognizable by any one. mostly aquatic insects. I made a single trip down the outlet of the lake and found in the rapid part of the Chironomus plumosus, Linn. The Plumed Midge.—This stream a fine station for collecting Parnid beetles. species is easily recognized by its great size (11 to 12 mm. in length of body); it is the largest of the genus. It is Annual Report for 1907 / Walnut Lake – Page 56 of 67 common at Walnut Lake, but would not be likely to be time when she reached the windward end of the beat, found so except by a collector specially looking for it. An and, heading the opposite way, after the manner of occasional specimen may be seen flying across the midges in copulation, in apparently active flight, lead the water from its place of transformation to find shelter return course to the leeward end of the beat. There they among the trees on shore. Near the water's edge one would separate, the male returning to the swarm, the will occasionally be flushed from a tree trunk or from an female leaving for parts unknown. She was always lost overhanging bough, and on sweeping the shore from view almost immediately. I could only see that in vegetation in sedgy areas with an insect net, one will departing her flight had no relation to the wind; she flew often be taken from the dry summit of a typha stem. But obliquely downward, usually in the direction of the lake, few of the adults are discoverable except by watching for but once or twice apparently in the opposite direction their evening flights. toward the trees. The whole mating act occupied hardly more than one or two seconds of time. Swarming and mating habits.—Chironomus plumosus appears on the wing for its mating flight at a time about The laying of the eggs I did not succeed in observing. midway between sundown and dark. Unfortunately, The triangle dredge brought up from the bottom a single before its appearance nightfall has covered the clump of Chironomus eggs in 30 feet of water, forming surrounding woods and meadows with blackness so large a mass it could hardly have been laid by any against which the midges cannot be seen at all; they are other of our species. It was taken July 9th at station 5, only visible against the background of the lighted sky placed in bottle of water in the laboratory, and there the above. Hence one cannot see them coming from their eggs hatched on the 11th and 12th. The young larvæ resting places to join the company in flight. How eagerly swam freely upward and outward to become aggregated I watched for this, only to have the curtain of darkness upon the lighted side of the bottle. Each still carried a fall to the edge of the horizon before any of the plumed little mass of unabsorbed yolk. Doubtless this is the time midges had been sighted. Then a few would appear of their distribution over the bottom. Doubtless this is the overhead; three or four or five of them, eight or ten time they get into the plankton in greatest numbers; the meters high, and would quickly fall to flying horizontally plankton chironomids are usually minute ones. By the back and forth upon a regular beat. Gradually they 13 of July about half of those larvæ that had hatched would be joined by others; but they never form thick were constructing such sort of cases on the bottom of clouds, as do many of the smaller species. The the bottle and on the paper label it contained as the individuals stand well apart in their flight, with usually scanty sediment in the bottle allowed. several decimeters space between them. After a little The further life history of this species has not been while one could determine by changing his base of traced. Dr. Johannsen has described larvæ and pupæ observation that a considerable area was overhung by from the Renwick marshes at Ithaca, N. Y. which he has the hovering midges. referred to this species with a high degree of probability. Their habit is to fly swiftly forward head to wind for a The larvæ I found by dredging in 100 ft. of water in distance of about 10 meters, and then holding the body Walnut Lake were not the same species described by to the same position still, to drift rather more slowly Dr. Johannsen; neither were those obtained earlier in the backward to the starting point. This is repeated season from whitefish stomachs; neither were these last continuously by all the individuals in the flight, though not the same as those I dredged. It is highly probable, quite synchronously. When a good breeze is blowing however, that this is one of several deep-water species they move quite horizontally, and in straight lines; when of Walnut Lake, for in addition to the occasional very it is calm their movements are a little less regular. There large pupa skins found floating on the surface, Mr. seems always to be enough movement of the air to Hankinson has taken the newly emerged imagos on the determine their position in flight, which is always head to surface over deep water. windward. Even at the height of 10 meters one could I was able to determine approximately the number of see by looking carefully that nearly all the individuals eggs produced by this species by capturing a newly were males. An occasional female could be recognized emerged female, keeping her until mature, dissecting out by her distinctly larger size. With a little practice the the ovaries and counting the eggs. The newly emerged females could be followed through the entire course of adult is still reddish in color, especially at the sutures their brief mating flight; for while the males appear to between body segments, the red color of the blood still hover with the swarm through the whole period of showing through the slowly darkening cuticle. The observation, each female flies but a few minutes. She ovaries contained in this case about 3000 eggs. could be seen entering the swarm, rising in flight as if coming from some resting place in the marshes. She Chironomus meridionalis Joh.—I observed the swarming would take her place in the company, falling into step, so and mating habits of this species also on several to speak, and moving back and forth at a proper interval, evenings. At station 1 small swarms could be observed in straight horizontal lines. Then, while in her windward almost anywhere along shore as darkness was falling. course, a male would be seen to approach, to grasp her The swarms maintained an elevation of but one to two from above with his feet, and the two would appear as meters above the ground. The flight of individuals was one for an instant. Then, having seized her abdomen head to wind always, through a distance of hardly more with his claspers he would turn about face just at the than a meter, then a drifting backward to the rear of the Annual Report for 1907 / Walnut Lake – Page 57 of 67 swarm, forward and backward, in endless repetition, not, surroundings, and bur-like with groups of these hairs however, in straight lines, as in Chironomus plumosus, projecting in all directions from them, were present. but with much irregular weaving up and down, and with a The larvæ entering the nymphæa tissue needs but constant shifting of relative positions in the swarm. The remove a few thin partition walls in order to have space females stay longer in the swarm in this species. I enough to live in. It spins about itself the usual thin watched one female twenty minutes from her entering tissue of silk, and for a covering uses the materials of the and then lost her without seeing the conclusion of her demolished air-space partitions. Over the outside of the flight. I observed copulation in a number of other older parts of its case, and in the vestibule of its instances; it occurs quite as in Ch. plumosus, and has chambers diatoms and other very minute algæ flourish the same sequel—the female departs immediately abundantly, as they do all over the outside of the stems. thereafter, and the male returns to the swarm and And the manner of life of these larvæ is not greatly resumes flying. different from that of their congeners on the pond Chironomus albistria Walker.—Mr. McDonald found this bottom. Doubtless they are more protected during larval species living in green petioles of Nymphæa advena, life; they show also some modifications of the minuter and showed them to me on my first visit to Walnut Lake. structures of the feeding organs to be mentioned in the I was greatly interested to know a species with such a following descriptions. habit, and suggested that he rear some of the larvæ. The larva when fully grown measures 16 mm. in length This he did, obtaining his first imagos on July 10th. The and 1 mm. in diameter. It is of the usual cylindric form, adults were not observed at large, and nothing is known of a bright transparent red color, with a reddish brown of their habits. Larvae and pupæ are described below. head. The two caudal tufts contain each six very close Formerly I found at the campus pond in Lake Forest, Ill., set yellowish hairs, and there are two isolated hairs the dead leaves of typha teeming with larvæ of the below the tufts above the anal gills. The latter are four chironomid Tanypus carneus, and I innocently supposed as usual, thick, obtuse and hardly longer than the anal they were eating the leaves, until I made an examination prolegs; there are no other abdominal gills. The claws of of their stomach contents. This revealed to me the fact the prolegs are obliquely U-shaped. The labial border that their diet within the leaves was practically the same (Fig. 19) is of a very unusual form, being elongate and as that of other chironomid larvæ living upon the pond deeply bilobed, with no very distinct teeth save the two bottom—diatoms and the minuter algæ—while the tissue very large ones that terminate its lobes, and that are of typha were not eaten at all; this was shredded and separated by a triangular space of their own width. used to cover the silken tubes within which the larvæ There are faint indications of two low teeth nearer the dwelt in the excavations in the leaves, much as others median line, and of five outside on each lateral margin. live upon the pond bottom. The epipharyngeal comb is poorly developed, consisting of a row of three obtuse, triangular tubercles (Fig 19 m). The larvæ of Chironomus albistria live in elongated excavations in the green nymphæa petioles, having one or more blackish minute openings to the outside. These openings, being slightly discolored, were an easy means of recognizing infested stems. The earliest of the leaves that reach the surface of the water were the ones most infested, and the longest internal chambers, with the Figure 19. Chironomus albistria Walker. m—The largest external openings leading into them, were found epipharyngeal comb of the larva; n—the labial border; both x near the base of these. However, many of the tunnels 55. were cut high up on young vigorous petioles, and looked as if made by the chironomus larvæ themselves from the The pupa measures 12 mm. in length. It is red in color, beginning; so I was curious to see whether these larvæ darkening with age with the appearance of the adult were eating green plant tissue. I examined the stomach pigmentation. It possesses the usual thoracic tufts of contents of half a dozen larvæ of different sizes, freshly respiratory filaments, sessile, short, spreading and very brought in from the field. In the smaller ones I found finely divided by successive branchings. Across the only algæ and silt. In all of the larger ones I found a little, apex of the 2nd abdominal segment on the dorsal side and in one of the largest, much, nymphæa tissue. there is a fine line of minute chitinous black teeth, which Certain parts of this tissue are exceptionally easy to scarcely extends down upon the sides. The postero- recognize—the internal hairs, for instance, which spring lateral expansion of the 8th abdominal segment ends in from junction cells in walls separating the normal air a digitate comb of about five posteriorly directed teeth, of spaces of the tissue of the petiole, and project into those which the middle one is longest and strongest, the spaces; these hairs are covered with microscopic second and fourth shorter and sub-equal, and the first prickles, and are easily recognizable even in fragments, and fifth minute or rudimentary, and before these on the while whole hairs were frequently found, and in the case lateral margin of the segment is a row of four slender of the one larva that had eaten most freely of the tissue, distant spinules. The bifid ventral appendage of the end whole junction cells fairly well isolated from their of the abdomen is slightly longer than the body of the caudal fin; the fringe of the fin is semi-circular in outline

Annual Report for 1907 / Walnut Lake – Page 58 of 67 and continuous over the two lobes; it is composed of rakers directed backward toward the mouth opening; very fine silky yellowish hairs, and is one-half longer than and that the front of the head is developed into a narrow, the 9th segment. rounded prominence, beset with hairs, the lowermost of which are often decurved and pectinated. The REMARKS ON TWO OTHER CHIRONOMUS homologies of all these parts are by no means clear as yet. The more important parts are designated by LARVÆ FOUND IN DEEP WATER IN tentative and provisional names in the explanation to the WALNUT LAKE, AND ON THE MEANS OF figure. The shape, number and proportions of the teeth DISTINGUISHING THE SPECIES. in the labial border and in the epipharyngeal comb have been found most useful hitherto in the discrimination of I have had for study two species of Chironomus Iarvae the species, and figure 21 and the excellent plates in the from Walnut Lake obtained from deep water, one taken monograph by Johannsen will abundantly illustrate the by myself with a triangle dredge in 100 feet of water, and sort of differences likely to be found between them. examined both fresh and preserved; the other taken from the stomach of a white fish by Mr. Hankinson. The former is apparently identical with the species I found making up the greater part of the food of the brook trout in Bone Pond near Saranac Inn in the Adirondacks in 1900 (figured in detail by Dr. Johannsen on pl. 49 of Bull. 68, N. Y. State Museum). What the species is, is not yet known. Likewise, it is not yet known to what species of adult the other Iarvae which the white fish were eating so extensively in April belongs. It is doubtless a smaller species; the larva lacks blood gills on the penultimate abdominal segment. It is quite like the larva of Ch. fulviventris as described in Bull. 86, N. Y. State Museum and figured in plate 22, Figs. 19 and 24-26; but it differs from that species in at least two characters of the sort that usually distinguish species in this genus. (1) The teeth of the labial border are similar as far out from the middle as the third in these two species, but of the Figure 21. Semi-diagrammatic figure of the buccal apparatus remainder each side, it is the seventh (Fig. 20q), and not of the larva of Chironomus viridicollis V. d. W., viewed from the fourth that is prolonged beyond the level of the tips of below, the mandibles, x, and maxillæ, y, spread out laterally, the others. (2) The three pieces of the epipharyngeal and the top of the mouth moved a little anteriorly so as to show comb are three-toothed in fulviventris; they are five- all of the epipharyngeal armature (based on drawings by Mr. H. rayed in the Walnut lake species (Fig. 20p). R. Stewart). The line i-i represents the labral margin of the mouth; the parts above it are on the front of the head, outside the mouth; the parts below it are in the roof of the mouth. The ill defined fringe of fine bristles along this margin has sometimes been designated as the anterior comb. f, the pedunculate palps (only their peduncles are shown in Miall and Hammond's The Harlequin Fly Fig 16), g, frontal sensory hairs; Figure 20. Unknown Chironomus larvæ from stomach of h, h, labral or external rakers; i, i, lateral papillæ; k, whitefish; p—epipharyngeal comb, x 310; q—labial border, x epipharyngeal (or posterior) comb; I, I, epipharyngeal or 55. internal rakers; m, m, lateral arms; n, n, anterior cross bar ;1 o, It should be obvious at once that the most immediate o, U-bar; p, maxillary palpus; q, lacinia of the maxilla; r, hypopharynx?; z, the labial border, heavily chitinized (in situ, and insistent need of such studies as that in progress at the mandibles swing obliquely downward against this border). Walnut Lake is further life history work upon these important species. In order to assist any one who may A simple mode of manipulation enables one to mount take up that work in the discrimination of species among preparations of the heads of chironomus larvæ for the the larvæ of the genus, I present herewith a semi- microscope to show the above designated parts. The diagrammatized figure (Fig. 21) of the mouth parts of the heads are cut off and boiled for a few minutes in a weak larva of Chironomus viridicollis, a species which I have solution of caustic potash, then mounted ventral side up bred from a sluggish stream (the Skokie), near lake in balsam after the usual methods. A slight pressure Forest and I designate in that figure the typical parts of upon the cover will usually cause the mandibles to swing the curious and complicated mouth apparatus in this outward, exposing fully the more important structures. genus. It will be observed in the living larva that the The parts may, of course be dissociated with needles mandibles do not oppose each other in the usual way, and placed in any desired position. but instead swing obliquely downward against the toothed edge of the labial border; that the epipharynx The larval cases of Chironomus.—As already stated for and the whole ventral border of the labrum and roof of Ch. plumosus, the larva begins a day or two after the mouth has developed an armature of combs and hatching to construct a case to dwell in. The basis of Annual Report for 1907 / Walnut Lake – Page 59 of 67 construction is the more or less silk-like secretion of the quietly, allow themselves to be picked up with the remarkable salivary glands, which hardens on contact fingers. I could not discover any place or time of with the water. It is spun out not in threads, but in swarming, nor find any considerable number of tenuous sheets of more or less flocculence, to which silt individuals on the wing at any given place. Yet the adheres readily, protectively coloring the whole exterior. abundance of the cast skins that float upon the surface Since the larva crawls into the bottom silt and fashions shows that a considerable number of imagos are its case there, it is probable that there is no voluntary emerging all the while. In Bull. 47, N. Y. State Museum, adding of pieces to the outside as with caddis fly larvæ, I published an account of the life history of this species but that the secretion holds fast automatically to with figures of larval and adult stages. whatever touches it. That it holds silt securely is The eggs are probably laid upon the surface of the evidenced by the figure in plate 75, which was made water, the female falling flat upon the water with wings from cases taken up in a dredge in 100 feet of water, outspread and liberating them there. I frequently saw sifted roughly, carried to the laboratory, and lifted out females floating thus at nightfall, but was not able to with a forceps on to a white plate before being demonstrate that they were ovipositing. Many other photographed. These are not portable cases, they are Mayflies liberate their eggs in this manner. The eggs mere run ways or silk-lined tunnels through the silt. doubtless settle to the bottom, tending apart as they fall, They are usually open at both ends, and may readily be and becoming scattered somewhat, according to the torn open anywhere. They are usually many times as depth and currents of the water. The larvæ live as long as the larvæ that live in them. The same diatoms shallow burrowers in the bottom silt. The length of the and other algæ are found adhering to them and to the larval life is unknown. When grown they swim to the bottom silt generally as are found in the larval stomachs. surface and transform there. The subimago emerges The cases are very fragile, many will not stand to be suddenly from a rent in the back of the old larval skin, its lifted out of the water by one end. They are not eaten wings expanding fully almost at once; it stands for an with the larva but are winnowed out. Such sweeping or instant on the surface and then flies away toward the fanning action of the fins as results from the labor that shore. This transformation occurs at any time of the day many fishes perform in the making of their nests would or night. The final moult, the casting of the subimago be more than sufficient to tear up the cases and dislodge skin occurs within 24 hours thereafter, the period the contained larvæ. intervening being spent in inactivity. The evening Fishes eat, and doubtless by preference, the larger following is probably the period of adult activity—the time larvæ. Some indirect evidence on this point was when the mating flight occurs, and when the eggs are obtained by comparing the sizes of a lot that had been laid, though observations are yet lacking upon these eaten with a sample catch taken from the lake bottom points. with the dredge. A short haul was made in 100 feet of I was able to determine at Walnut Lake the egg-laying water and about half a bushel of black bottom mud was capacity of this species. I captured sub-imagos when brought up and sifted for Chironomus larvæ. These leaving the water or when resting on shore, kept them were separated by Mr. McDonald according to sizes into through their final moult until fully adult and obtained four groups and counted with the following results: their eggs. I was preparing to get the eggs by dissection of my first specimen when I made a curious discovery. I placed the fully adult female upon water in a watch-glass and with fine scissors, snipped off her head. Immediately she began depositing her eggs* in the water beneath her, pouring them out rapidly from both Then a well preserved lot of larvæ from the stomach of a oviducts, and not ceasing until they were all deposited whitefish (No. 680*) were likewise similarly separated (this I determined by dissection later). This occupied not into groups and counted, with the following results: more than two minutes. A partial count and estimate of the number of eggs thus laid put it at about 9000. The method thus found being so easy of application, I repeated the performance with a number of other females, obtaining somewhat smaller numbers, though the lowest estimate was 7850 eggs. The average Clearly the fishes eat the larger larvæ. number was about 8000.

*This fish had eaten also 5 Sayomyia larvæ, 1 Hexagenia larva and a The eggs are translucent whitish, oblong, broadly little mussel, Pisidium. rounded on the ends, and show no visible micropyle. They are already filled at laying with minute yolk balls. Hexagenia variabilis Eaton.—This species is common at The chorion is very thin and transparent, and the Walnut Lake, though little in evidence by day. An gelatinous envelope is exceedingly scanty, and at first occasional specimen can be seen flying upon little adhesive, insomuch that the eggs roll freely about in transformation from open water to the woods on shore. the water. However, after they have lain in the water a At rest on shore, they are conspicuous enough because few hours a gelatinous connection is easily seen of their large size. They sit rigidly, and, if approached Annual Report for 1907 / Walnut Lake – Page 60 of 67 between two eggs that lie in contact, and any silt in the at the lower level of the swarm (four or five meters above water becomes attached to them. These eggs being the water), it lifts its head and rises rapidly again in flight. unfertilized, showed no signs of further development. And the whole company flying and falling thus, weaving up and down in vertical lines, and passing and repassing *This reaction does not follow like treatment of any other Mayfly on which I have tried it—not even the closely allied H. bilincata Say. each other, create a scene of great animation. It was most interesting to see this automatic response on About as soon as the flight of the Ephemera swarms is the part of the female to an unusual stimulus, leading to well established, Chironomus plumosus appears in the the complete performance of the last important act of her horizontal flight that I have described on preceding life. I doubt not that it may be brought about in other pages. Chironomus meridionalis also appears nearer the ways. Mr. Viereck showed me a pair of this species that ground. Then, as the darkness deepens, the May-fly he had caught somewhere in Pennsylvania on his way to Cænis, the smallest of all the Ephemera, comes out to the Ithaca meeting. Having no cyanide bottle he killed perform in little swarms, which one may see if he chance them by pinching the thorax, whereupon the female to come close enough; they are hardly visible for a extruded into the air in two oblong packets the entire distance of more than a few feet. These are males also, contents of her ovaries. which weave up and down in straight lines hardly rising higher than one's head. Along the wave-washed, marl-floored shallows between stations 1 and 7, and between stations 7 and 15 I could Last of all the visible performers, Heptagenia, appears find any evening a number of adult females flying. They when it is almost too dark to see, in small companies of were certainly "going through the motions" of laying males, which weave up and down obliquely, flying eggs, falling flat upon the surface with wings outspread, forward and upward, head to wind, and drifting and rising, flying on, and falling again, or sweeping along for settling downward and backward to the starting point. a time close to the jutting edge of the sedge zone at the How high these go could hardly be told on the several shore. But I caught a dozen or more of them at different occasions when I watched them, the white forms being times and they were all spent females, with no eggs little visible against the sky (one could see them but a remaining. This, always just as darkness was closing in. few feet) but they descend to a level easily within reach They had laid their eggs probably earlier in the evening, of a net. Whether females come near these swarms and perhaps farther out from shore. The larvæ are when in search of mates I was wholly unable to observe. found mainly in deeper water. Detailed knowledge of the mating and ovipositing habits of this species will be gleaned with great difficulty. A Heptagenia pulchella and the twilight procession of search light which we brought into requisition at station I swarming species.—This is in every respect a very was of no practical assistance in observing any of the different May-fly, more nocturnal, more secretive, more flights above described. fragile, with depressed larvæ that cling closely to stones, preferably on wave-washed shores. The Iarvae are I reared this species at Saranac Inn, N. Y., in 1900, and eaten by shore-feeding fishes, and are easily collected published a description of the larvæ in Bull. 47, N. Y. by picking them from stones quickly lifted out of the State Museum, p. 421 (Pl. 15, Fig. 15). The importance water, but the imagos are infrequently seen. of the larvæ as fish food may be gathered from the facts Subimagos, at leaving the water fly to lights Mr. Hankinson has furnished elsewhere in this report. occasionally; they transform within twenty-four hours and The food of the larvæ consists of such dead plant probably mate and oviposit the night following their last materials, and living algæ intermixed therewith as they moulting, though this has not yet been observed. may find about the under surfaces of the stones to which they cling. It is intermixed with much silt and with some There is a regular procession of crepuscular insects sand. I examined a number of specimens carefully and appearing on the wing for their mating flight on the shore could find no animal remains whatever. of Walnut Lake during July. Directly after sundown the little red-eyed fly, Synechis simplex Walker, appears in ill defined companies darting about in irregular, though II. ANNOTATED LIST OF THE SPECIES chiefly horizontal flight, usually near, but not over the OBSERVED. water. Then the beautiful May-fly, Ephemera simulans, appears in companies of males over the edge of the Plecoptera. Stoneflies. water. The flight of one of these companies is a most delightful performance to witness, it is so light and 1. Chloroperla brunneipennis Walsh. Two males of this graceful, and appears, withal, so exhilerating. Yet it is all species came to a trap lantern set by the aquaria on the up and down in vertical lines. With upturned head each outlet of Walnut Lake on the night of July 1st. They were individual flies rapidly upward, mounting quickly to a the only stone flies seen. height of ten or fifteen meters, then spreading its wings out horizontally it falls upon them, with long fore legs Ephemerida. Mayflies. extended forward and longer tails extended backward 1. Ephemera varians Walsh.—Swarming flights full length, rudderlike, keeping it always head to wind. (described above) of thi-species I observed off stations 1 Thus it descends floating on the air, yet not drifting, until, and 15. The species was apparently common earlier in Annual Report for 1907 / Walnut Lake – Page 61 of 67 the season, for it would have been hard to get during my found young larvæ abundant at station 1, and sifted out stay so many specimens as Professor Hankinson took quite a number of them from the bottom marl with a on the 29th of May at station 46. The larvæ were taken sieve net. There were taken from most of the shore at a number of stations on the softer marl bottoms. Their stations at different times during the season. The cast food consists of marl and the substances intermixed nymphal skins were found associated with those of the therewith. It is readily dissected out of the alimentary following species, which see. canal as a cylinder of apparently pure marl, which when 2. Dromogomphus spinosus Selys.—This species was crushed on a cover glass reveals scanty amounts of coursing the surface of the lake with the foregoing one remains of filamentous algæ, and of the disintegrating late in June, and would alight once in a while on the fragments of the higher plants from shore. I could boat, where two specimens were captured. I found the discover in it no animal remains whatever. cast nymphs skins at station 27, where there is a narrow 2. Hexagenia variabiliis Eaton.—I took adults of this beach of sand, some three feet wide, with stunted sedge species on every day of my stay at Walnut Lake. Mr. growth at its landward side. They lay at the rear of the Hankinson took a subimago in transformation on the sand, among the projecting sedge roots, and were hard 25th of June. His fish food data will show the wide to find, though not uncommon. The bottom slopes seasonal and dietary range of the species. I have rapidly here, and is silted with marl and strewn with already given an account of its habits so far as known. coarse gravel. Bottom collecting on such a shore should find the larvæ. 3. Heptagenia pulchella Walsh.—Probably occurs at all the stations where there are stones or timbers to which 3. Basiæschana janata Say.—A single cast larval skin of the larvæ can cling. They are easily collected in this species was found clinging to a stem that overhung abundance at station 23. While we were coursing round the outlet brook about 100 yards distant from the lake. with a searchlight in the bow of the boat at station 54 a 4. Aeschna clepsydra Say.—Occasional adults of this number of subimagos, apparently just risen from the species were seen coursing the lake during July. One water, came to the light. I have given above brief and male captured served for identification. A few large fragmentary notes on the habits of the species. nymphs of the genus that may as well as not be of this 4. Callibætis ferruginea Walsh.—Of this species I species were collected during May 4 collected at station 7 a few males, swarming just before 5. Anax junius Drury.—This ubiquitous species, so dark, weaving up and down in a small company, and a common to the southward, was at Walnut Lake rather single female, swept from a clump of Decadon near by— rare. I saw but one or two specimens flying. I captured a July 7th. Although I did some collecting hereabout, I did single nymph at station 7. not find the larva. 6. Macromia illinoiensis Walsh.—This fine species is 5. Blasturus cupidus Say.—Two female subimagos of very common about the chara beds on the bottom of the this species were found floating on the surface at station lake, especially where the growth is sparse, exposing flat 225 on the 14th of May, probably having drifted out with bottom areas on which the larvæ may lie hidden. There the wind from shore; this is not characteristically a deep- are few finer examples of protective coloration than water form. these larvæ present, nevertheless, they are much eaten 6. Ephemerella excrucians Walsh.—A few larvæ of this by fishes. If overturned by the fishes in fanning the species were collected at stations 6, 26 and 28 during bottom, they would be readily seen with the light yellow the month of May. color of the under surface of the body exposed. I took larvæ with the triangle dredge at station 4 and in the 7. Ephemerella sp.—A single curious larva with deeper water opposite; also with a sieve net at station I, prominent head tubercles, was taken on the 26 of May and they have been taken in many other places in the (Coll. No. 927). lake, always in connection with a scanty growth of chara. 8. Cænis diminuta Say.—Imagos and subimagos of this Mr. McDonald found larval skins of this and the next species came to our trap lantern at station 1 in some following species on the sedges at the bank at station numbers on the nights .of 7th, 9th, and 13th of July. I 34. No adults were observed. observed the males swarming in their flights at stations 1 7. Epicordulia princeps Hagen.—This species was and 7. I took a few larvæ in a triangle dredge at station constantly seen in flight over the lake. None were 4, and in a sieve net at station 7. The larvæ are so small captured, however. Being easily recognizable in flight, it and cling so closely to the stems, even when withdrawn was not deemed desirable to make the effort necessary from the water that they are not often seen. to catch even a single specimen. The copius masses of gelatinous egg strings seen commonly about the borders Odonata. Dragonflies and Damselflies. of the lake hung upon projecting stems just below the 1. Gomphus spicatus Hagen.—This species was flying surface of the water, doubtless belonged either to this or not uncommonly when I first arrived at the lake on June to the species next following. I took larvæ of this species 26, and a few specimens were captured when they at stations 1 and 77 and Mr. McDonald took cast skins alighted on the boat that day and the day following. I from shore at station 34 as noted above.

Annual Report for 1907 / Walnut Lake – Page 62 of 67 8. Tetragoneuria cynosura Say.—This species was seen ovipositing by dipping the tip of the abdomen rather common, one or two specimens were taken on my repeatedly and rapidly into the surface of the water. first visit for the sake of certain determination. I found 20. Tramea lacerata Hagen.—Two adults of this species, the larvæ abundant at station 7 and they were collected apparently, were seen but not taken. No larvæ of this sparingly at other places. Doubtless some of the egg genus were encountered. masses referred to above belonged to this species. I have figured these in Bull 47, N. Y. State Museum, p. 21 Calopteryx maculata Beauvois.—This species 491. swarmed about the outlet, more abundantly in the rapid places in the stream, where many females could be 9. Somatochlora sp.—Several young larvæ that I took seen busily depositing their eggs in the trailing and with sieve net at station 7 are nearest this genus, but are hardly submerged stems of Potamogeton nuttalli. not like those of any of the known larvæ described therein. 22. Lestes unguiculata Hagen; 23. Lestes rectangularis Say.—These two species were both found among the 10. Perithemis domitia Drury.—I saw a single male of vegetation on the west shore of the lake—single male this species sitting on a nymphæa leaf at station 54, and specimens of each. though I did not capture it, I was close enough for certain identification. 24. Lestes vigilax Hagen. 25. Lestes inequalis Walsh.— These two species were found on the outlet a hundred 11. Celithemis elisa Hagen.—This beautiful insect was yards distant from the lake—single male specimens of very common all about the lake. During sunshine the each. adults were flying in pairs all about the bulrush beds, while the solitary males exercised "squatter sovereignty" 26. Argia violacea Hagen.—Common all around the lake over little areas, perched on the top of some tall stem and down the outlet; more characteristic of flowing than standing in the midst of his domain. During the first of still water. week of July the cast larval skins were hanging thickly to the bulrush stems. I collected the nymphs at station 7. 27. Nehallennia irene Hagen.—Abundant about the outlet. Could be swept in the sedge zone about the lake 12. Celithemis eponina Drury.—I took a single larva of almost anywhere. this species at station 7, and I think I saw one or more of the adults in flight. 28. Enallagma hageni Selys; 29. Enallagma ebrium Hagen; 30. Enallagma civile Hagen.—All found about 13. Leucorhinia intacta Hagen.—Common, especially the lake border, the first most common, the last least about the nymphæa beds. I collected the larvæ at common. Transforming in the bulrushes everywhere, station 7. but no attempt was made to identify the larvæ. 14. Sympetrum rubicundulum Say.—This species was 31. Enallagma antennatum Say.—Very common about just becoming common on the wing at the time of my the outlet. departure. That was too early for many Sympetra. Doubtless other species would be found later in the 32. Enallagma signatum Hagen; 33. Enallagma pollutum season. Hagen.—Both very common, especially about stations 15 and 54. The latter is the latest flying of all Odonata, 15. Pachydiplax longipennis Burmeister.—A few pairs being seen on the wing repeatedly when it was too specimens of this species were seen in June, and one dark to tell without capturing them in a net and looking was captured. The larva apparently was not more closely, whether they were big Mayflies encountered. (Hexagenia) or not. 16. Mesothemis simplicicollis Say.—I captured a single 34. Ischnura verticalis Say.—Rather uncommon; taken adult of this species July 14, by the outlet to Evans’ only a few times. pond, near Walnut Lake. Mr. Hankinson took two larvæ at Orchard Lake on the 18th of June. Hemiptera. 17. Ladona exusta Say.—I captured a single adult of this The following species of this order were kindly species at station 20 on June 26. determined by Mr. J. R. de la Torre Bueno of New York 18. Libellula luctuosa Burmeister (= basalis Say).—Not City: uncommon about the shallows bordering the lake; Corisa sp.—Young individuals not uncommon about belongs to the fauna of pools and shallow ponds rather submerged vegetation. than to that of lakes. Notonecta variabilis Fieb.—Common at station 7. 19. Libellula pulchella Drury.—This is an abundant species of some importance to fishes that feed in Ranatra quadridentata Stal.—Adults were rarely seen, shallow water. In all collecting with hand nets from the but half grown larvæ were common at many places in bottom it was encountered. It was abundant at stations shore vegetation. A few floating typha stems bristling 1 and 7. In such places the females could frequently be with the curious appendages of the contained ranatra eggs were found at station 7.

Annual Report for 1907 / Walnut Lake – Page 63 of 67 Belostoma (formerly Zaitha) sp.—A few adults were Hydroptilidæ. taken with a sieve net from the ditch back of station 7. 8. Agraylea sp.—Trap lanterns drew a few female Gelastocoris sp.—This undescribed species was specimens during July. common on the narrow strip of sandy beach at station 9. Oxyethira sp.—A single female captured on the 25th 27. of June bears the number 1313. Acanthia sp.—Not uncommon on mud at edge of water. 10. Hydroptila sp.—Four larvæ and one pupa in Gerris marginatus Say; Gerris sp. (undescribed).— parchment cases 6 mm. long by 1½mm. wide, were Common everywhere on the water at the edge of the taken from Nymphæa petioles July 12th. standing vegetation. 11. Hydroptilid larva of undetermined genus, in parchment cases 4 mm. long by 1 mm. wide at the one Neuroptera. end tapering to ½ mm. wide at the other, taken with the Sialis infumata Say.—This orl fly was very abundant at preceding species, and attached like the cases of that Walnut Lake early in the season. Larvae were collected one to the erect nymphæa petioles by two hold fasts at on the bottom in many places during April and May, and each end. These were obtained while collecting the they were then being eaten commonly by fishes. About stem-infesting Chironomus and Hydromyza larvæ, and the latter end of May the adults were abundant; those in were very common; they might have been obtained in the collection bear the date of May 23rd. I took off great numbers. station 3, in thirty feet of water, a half-grown larva of the A large number of additional adult Hydroptilidæ were next season's brood. obtained by the trap lantern on the nights of the 25th of Chauliodes rastricornis Say.—A few young larvæ, June and the 7th, 12th and 13th of July, but being mostly probably of this species were found singly crawling on females, preserved in alcohol, they are hardly the under surfaces of nymphæa leaves. identifiable. Hydropsychidæ. TRICHOPTERA. Caddis flies. 12-23. Four species of the genus Hydropsyche came to Determined by Dr. C. Betten. the trap lantern on the 25th and 26th of June, and 12th and 13th of July; nearly all females. Phryganeidæ. Likewise, 3 species of the genus Plectrocnemia, and two 1. Neuronia semifasciata Say.—One female was of Holocentropus, one of each of these latter being very collected on May 31st (No. 936) and another came to a common. A species of Tinodes is likewise represented lighted window of the laboratory on July 7th. in the lantern catch of the same date by a number of 2. Neuronia concatenata Walker.—A number of females. Several larvæ of Chimarrha, and of one other specimens came to the window with the preceding undetermined Hydropsychid were taken from the rocks species July 7th; two others, undated, bear the collection in the outlet of the lake on July 10th. number 1383. Leptoceridæ. Limnophilidæ. 24. Molanna cinerea Hagen.—This species swarmed 3. Platycentropus hostis Hagen.—One male (No. 1383). around a search light that was carried in the prow of the boat at station 54 on the night of July 13th, and a few 4. Larvae of an undetermined Limnophiline, in cases of were taken. A few additional came to the trap lantern. vegetable matter covered with small bits of mussel shells and stones (the larger 33 mm. long) were taken, 4 on 25. Triænodes ignita Walker.—This species came April 6th, and 4 on April 7th (Nos. 25 and 30). commonly to the trap lantern, a few on the 25th of June and on the 7th of July, and many on the 13th. 5. Another Limnophiline larva, in a case ballasted after the manner of the case of Goera, was taken on the 10th 26-35.—Four species each of Oecetis and Leptocerus, of July. one Leptocella and one Setodes, came also to the trap lanterns with the foregoing on the 25th of June and the Sericostomatidæ. 7th to the 13th of July. A few of these represented in 6. Heliocpsyche sp.—Several larvæ were taken from some numbers by both sexes, will doubtless later be stones in a riffle in the outlet of Walnut Lake (the location more specifically determinable. for Parnid beetles mentioned elsewhere) on July 10th; At least 35 species are represented in the collection, and a single adult was swept from the sedges on the nearly all obtained in the trap lantern on four favorable adjacent bank. evenings. The material was not adequately cared for, 7. Lepidostoma sp.—One male, July 12th. being merely dumped into alcohol; it is sufficient, however, to indicate that there is a good caddisfly fauna in Walnut Lake to reward the more careful labors, of the future collector.

Annual Report for 1907 / Walnut Lake – Page 64 of 67 Coleoptera. Erioptera septentrionis, O. S.; Geranomyia canadensis, Westw.; Ulomorpha pilosella, O. S.; Limnophila Haliplus ruficollis, DeG.—Three adult specimens I took quadrata, O. S.; Rhamphidia flavipes, Macq.—All came with a seive from the trash in the ditch back of station 7 to light; all could be collected by sweeping under the on July 11th. Though especially sought for, not a single edges of the tree growth on shore. Dytiscid was seen. Bittacomorpha clavipes.—A ditch back of the Decadon Gyrinidæ were not very common, but could be found in beds at station 26. The north inlet to the lake sheltered the more sheltered places among shore vegetation. this species in abundance. Gyrinid larvæ were taken not infrequently. I took a small Tipula sp. Common throughout the sedge zone. one at station 1, and a larger one in deeper water at Station 7. A large one taken by Mr. McDonald at station Toxorrhina magna O. S.—A single female specimen 47, and put in a vial of water to be brought home alive taken from a boat as it flew overhead at station 15 just with some larvæ of Chironomus albistria, was of a before dark on July 8th. beautiful transparent red color when I received it, half an hour later; but three of the midge larvæ had become CULICIDÆ. Mosquitos. white; the color was transferred with their blood. Psorophora ciliata Fabr.—A few specimens only of this A single adult Tropisternus was taken on June 26th. species came to the trap lanterns. A number of small larvæ of Hydrophilidæ were taken Anopheles punctipennis Say.—Common; many taken in with a seive net in the ditch back of station 7. trap lantern. A few specimens of Berosus sp. came to a trap lantern Anopheles maculipennis Meigen.—Not common; but few set beside the aquaria on the outlet the night of July seen. 12th. Culex perturbans.—The predominant mosquito, whose Macronychus glabratus Say.—Abundant on stones in biting was not uncommonly bad. the rapids a mile from the lake—the station for the following Parnidæ also. Sayomyia punctipennis Say.—Abundant; taken by thousands in the trap lantern when set with out-look over Stenelmis sp.—Likewise abundant. the lake. Larvae perhaps of this species were eaten by Elmis bivittatus Lee.—One specimen taken. white fish.

Elmis quadrinotatus Say—Common. CHRIONOMIDÆ. Midges. Ancyronyx variegatus.—One specimen taken. The species named below have been determined by Dr. Galerucella nymphæa—Common about the nymphæa O. A. Johannsen of Cornell University: beds, the larvæ feeding in considerable numbers on the Rhyphidæ. leaves. Rhyphus punctatus (trap). Donacia palmata—Common about nymphæa beds. Chironomus plumosus, Linn. Donacia. sp.—Less common, about the Scirpus covered areas. Tanypus monilis (some in trap) numerous. Tanypus sinuosa. DIPTERA. Protenthes culiciformis. Tipulidæ. Crane flies. Procladius pusillus (trap). Goniomyia subcinerea O. S.; Goniomyia blanda, O. S.— Came commonly to light, the former in greater numbers. Chironomus meridionalis (numerous). Limnobia cinctipes Say—Under linden trees on shore; Chironomus tentans. rarely attracted to light. Chironomus albistria (bred). Amalopis inconstans O. S.—In deep shade on shore; Chironomus similis (numerous). rarely attracted to light. Chironomus scalaenus var. (trap). Erioptera chlorophylla, O. S.—One of the commonest Tipulidæ at Walnut Lake, if not the commonest. It could Chironomus pallidus (trap). be found by sweeping vegetation anywhere near shore. Chironomus devinctus (trap). Taken in the trap lantern every night, and often in considerable numbers. Chironomus brunneipennis (trap). Antocha opalizans, O. S.; Erioptera straminea, O. S.; Chironomus halteralis (trap) numerous. Erioptera caloptera, Say; Erioptera parva, O. S.; Chironomus decorus. Annual Report for 1907 / Walnut Lake – Page 65 of 67 Chironomus plumosus Chironomus nigricans III. AN AQUATIC GALL ON THE YELLOW WATER LILY, Nymphæ advena. Chironomus viridicollis. While collecting the larvæ of the midge Chironomus Cricotopus trifasciatus (some in trap) numerous. albistria Walker, from their holes in the petioles of Cricotopus sylvestris. nymphæa Mr. McDonald and I frequently came upon galls associated with them in the stems. These galls Metriocnemus exagitans (trap). appear to be the first made known upon a member of the Tanytarsus flavellus (trap). water lily family (Nymphæaceæ); also the first known to be made by a member of the dipterous family Tabanidæ. Scatophagidæ; also the first to be found deeply and These and the following families have been determined constantly submerged. Therefore a brief account of by Mr. D. W. Coquillett of Washington, D. C.: them should not be without interest. Tabanus lineola Fabr.; Chrysops striatus O. S.; Chrysops plangeus Wied.; Chrysops niger Macq.—All common along shore. Stratiomyiidæ. Odontomyia vertebrata Say; Odontomyia plebeja Loew.—Occasionally seen flitting over vegetation about the shores. Egg masses were rather common on Figure 22. Gall-bearing petioles of Nymphæa advena. a, projecting bur-reed leaves. external views of the gall; the dotted circle marks the epidermal Leptidæ. window, through which the adult emerges. b, the gall cut open, showing the larva of Hydromyza confluens within. Chrysopila proxima Walker.—Common at the outlet. The galls are rounded swellings upon the petiole, Scatophyagidæ. distending it and increasing it by a fifth to a third its Hydromyza confluens Loew.—This species, which normal diameter (Fig. 22). They may occur anywhere, makes galls in the petioles of nymphæa leaves is except close to the surface or close to the bottom of the especially discussed further on. water. They are placed singly along the petiole, but occasionally are close enough together to appear Empididæ. superficially confluent. They occur most frequently upon Syneches simplex Walker.—This is the species that the stalks of the earliest of the leaves that reach the leads the procession of swarming species after surface (not at all upon the short stalked and wholly sundown, as detailed in preceding pages. submerged leaves of earliest spring), and very sparingly upon the later leaves. On a vigorous plant with eleven Cyrtidæ. floating leaves and two flower stalks, examined at station Ogcodes costatus Loew.—On willow tree overhanging 26 on July 12th, nine pupæ and three larvæ were found water at outlet. in the petiole of the oldest leaf, while three were found in the two petioles next younger. Probably the attack of the Syrphidæ. gall maker begins when the first leaves reach the Eristatis bastardi Macq.—Over shallow water about surface in late spring; then they have their first aquatic plants everywhere. opportunity to reach the proper place of oviposition by crawling down the stalk. Eristalis flavipes Walker; Eristalis transversus Wied.— Common about the shores. The insect that causes the gall to grow is the larva of the fly Hydromyza confluens Loew (family Scatophagidæ). Helophilus conostonus Will.—Common on iris flowers in No observations were possible upon any stages except the edge of the outlet. the later larval, and pupal, and the transformation to the Ephydridæ. adult. The cavity within the gall is rather close fitting until the larva is well grown, but becomes larger and its walls Hydrillia hypoleuca Loew.—Swarming upon white water become discolored later. Just before transformation to lilies, blackening the flowers within by their abundance. the pupal stage the larva eats a hole out to the epidermis, and returns to the center of the cavity; this hole is a passage of exit for the adult, which then has only to break through the transparent epidermal window to gain its liberty. The grown larva measures 9 mm. in length and 2 mm. in greatest diameter; it is shorter and thicker when

Annual Report for 1907 / Walnut Lake – Page 66 of 67 contracted. The body is of a somewhat fusiform outline, rather obtuse at each end, gradually thickened to the fourth or fifth segment, and then slowly tapered posteriorly. The color is white. No head is visible, but only a blackish mouth at the front end, below. A perforate cribriform plate of an inconspicuous brown color at each side of the prothoracic segment close behind the mouth terminates the longitudinal tracheal BOARD OF GEOLOGICAL SURVEY, 1908. trunk of each side; this is shown at d in Fig. 6, dissected EX OFFICIO: out entire. The air trunks end posteriorly in three pairs of radially placed slits, the lower one of which has its THE GOVERNOR OF THE STATE, margin prolonged in a stout triangular sharply pointed HON. F. M. WARNER, President. spine. This spine is shown at the end of the body in THE PRESIDENT OF THE STATE BOARD OF EDUCATION, Figure 6a; it is shown in side view enlarged more at HON. D. M. FERRY, JR., Vice-President Figure 6b; and the end view of spiracular aperatures of THE SUPERINTENDENT OF PUBLIC INSTRUCTION, both air trunks are shown in their relative positions at HON. L. L. WRIGHT, Secretary. Figure 6c. The form and position of this spine suggest that it may be used to break open the walls of air spaces BOARD OF SCIENTIFIC ADVISORS. in the nymphæa tissues, as a correspondingly placed PROF. W. B. BARROWS. spine connected with the spiracle in the larva of the PROF. W. J. BEAL. beetle Donacia is used to puncture the tissues from the PROF. W. H. HOBBS. outside. PROF. L. L. HUBBARD. PROF. F. C. NEWCOMBE. PROF. J. REIGHARD. PERMANENT STAFF LANSING

ALFRED C. LANE, State Geologist. W. F. COOPER, Assistant. Figure 23. The larva of Hydromyza confluens. a, side view of H. R. WIGHT, Clerk. the whole larva; b, the caudal peritreme spine, greatly HOUGHTON enlarged; c, posterior view of the respiratory aperatures; d, the prothoracic spiracular apparatus, removed and enlarged (the A. H. MEUCHE, Engineer in Charge. mark close behind the mouth in the upper figure shows the location of this.)

At transformation, the larval skin contracts into a puparium, the anterior spiracular apparatus becomes pushed out upon each side to form a prominence as high as wide, and the perforations appear as minute roughness upon its surface; the posterior spines remain projecting; the contracted body within shapes itself into the pupa, and between this and the anterior end of the puparium is clearly seen through the transparent wall the furcated buccal armature that lined the larval mouth. The decaying of the tissues about the walls of the gall when the leaf gets old, together with the perforation of the wall by a passage for exit, weaken the stalks, and they break readily across the top of the gall during the pupal stage of the contained insect. Thus the pupæ are readily obtained. Some of those obtained on the 12th of July were placed alive in a dry bottle, and several of these transformed the next day. About the same time adults were noticed commonly about the lily beds, sitting upon the leaves, and taking flight readily upon approach. On the night of July 13th, while we were boating with a search light about station 54, they flew in some numbers to the light. This species will doubtless be found commonly about Nymphæa beds in the United States, notwithstanding that it appears to have been reported hitherto only from Canada.

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